What is the Action Mechanism of Gabapentin ? Is Gabapentin Addictive ?

The chemical structure of gabapentin (Neurontin) is derived by addition of a cyclohexyl group to the backbone of gamma-aminobutyric acid (GABA). Gabapentin prevents seizures in a wide variety of models in animals, including generalized tonic-clonic and partial seizures.

The exact mechanism of action with the GABA receptors is unknown; however, researchers know that gabapentin freely passes the blood-brain barrier and acts on neurotransmitters.

Gabapentin has a cyclohexyl group to the structure of neurotransmitter GABA as a chemical structure. Even though it has a similar structure to GABA, it does not bind to GABA receptors and does not influence the synthesis or uptake of GABA.

Gabapentin works by showing a high affinity for binding sites throughout the brain correspondent to the presence of the voltage-gated calcium channels, especially alpha-2-delta-1, which seems to inhibit the release of excitatory neurotransmitters in the presynaptic area which participate in epileptogenesis.

Even though there is no evidence for direct action at the serotonin, dopamine, benzodiazepine, or histamine receptors, research has shown gabapentin to increase total-blood levels of serotonin in healthy control subjects.

The elimination half-life of gabapentin is 5 to 7 hours, and it takes two days for the body to eliminate gabapentin from its system.

One benefit of gabapentin use is its mild side-effect profile. The most common side effects are fatigue, dizziness, and headache.

Gabapentin has no activity at GABAA or GABAB receptors of GABA uptake carriers of brain. Gabapentin interacts with a high-affinity binding site in brain membranes, which has recently been identified as an auxiliary subunit of voltage-sensitive Ca2+ channels. However, the functional correlate of gabapentin binding is unclear and remains under study.

Gabapentin crosses several lipid membrane barriers via system L amino acid transporters. In vitro, gabapentin modulates the action of the GABA synthetic enzyme, glutamic acid decarboxylase (GAD) and the glutamate synthesizing enzyme, branched-chain amino acid transaminase.

Results with human and rat brain NMR spectroscopy indicate that gabapentin increases GABA synthesis. Gabapentin increases non-synaptic GABA responses from neuronal tissues in vitro. In vitro, gabapentin reduces the release of several mono-amine neurotransmitters.

Gabapentin prevents pain responses in several animal models of hyperalgesia and prevents neuronal death in vitro and in vivo with models of the neurodegenerative disease amyotrophic lateral sclerosis (ALS). Gabapentin is also active in models that detect anxiolytic activity.

Although gabapentin may have several different pharmacological actions, it appears that modulation of GABA synthesis and glutamate synthesis may be important.

Is Gabapentin Addictive ?

Asking about the signs someone is addicted to gabapentin first begs the question: What is gabapentin?

To answer that question requires putting gabapentin in perspective as a pharmaceutical drug that, while providing relief to thousands of people for nerve pain, also has the potential for abuse. It isn’t an opioid, but it has found a niche audience among those who take it recreationally, and for doctors who began to seek alternatives to narcotics as the opioid epidemic reached its apex, it seemed like a safer alternative.

In 2016, gabapentin was the 10^th most prescribed drug in the United States, with 64 million prescriptions written that year . That was up from 39 million prescriptions written only four years earlier, in large part because “gabapentin, an anticonvulsant and analgesic for postherpetic neuralgia, has been thought to have no abuse potential despite numerous published reports to the contrary,” according to a 2018 article in the journal Psychology of Addictive Behaviors.

In that particular article, researchers analyzed data from a study of drug users in Kentucky who reported using gabapentin for non-medical purposes. Their findings? “Overall, the sample reported having initiated gabapentin more than 10 years earlier after having it prescribed for a legitimate, though generally off-label, medical indication (e.g., pain, anxiety, opioid detoxification). Participants reported use of gabapentin in combination with buprenorphine, other opioids, cocaine, and caffeine to produce sought-after central nervous system effects (e.g., muscle relaxation, pain reduction, sleep induction, feeling drunk, and feeling ‘high’).”

Gabapentin, such studies reveal, can be problematic. Whether used in conjunction with other drugs or on its own, it can be abused, which makes it a substance of concern. To understand the signs someone is addicted to gabapentin, however, requires some knowledge of what it is, where it comes from, how it works and how it can be addictive.

Comparative Studies

Gabapentin and lamotrigine have been compared in an open, parallel-group, add-on, randomized study in 109 patients with uncontrolled partial epilepsy and learning disabilities. The two drugs were similarly efficacious, with similar incidences of adverse events and serious adverse events. Neither lamotrigine nor gabapentin exacerbated any of the challenging behaviors observed in these patients.

The most common adverse reaction to gabapentin was somnolence, which was mostly reported during the initial titration phase.

In a double-blind comparison of gabapentin and lamotrigine in 309 patients with new-onset partial or generalized seizures, the target doses were gabapentin 1800 mg/day and lamotrigine 150 mg/day.

Severe adverse events were reported in 11% of patients taking gabapentin and 9.3% of patients taking lamotrigine. Two patients had serious adverse events thought to be related to the study drug; one took an overdose of gabapentin and the other had convulsions with lamotrigine. The most frequent treatment-related adverse events in both treatment groups were dizziness, weakness, and headache; 11% of patients taking gabapentin and 15% of those taking lamotrigine withdrew because of adverse events. There was an increase of over 7% in body weight from baseline in 14% of the patients taking gabapentin and 6.6% of those taking lamotrigine. There were benign rashes in 4.4% of those taking gabapentin and 11% of those taking lamotrigine.

The hypothesis that both amitriptyline and gabapentin are more effective in relieving neuropathic pain than diphenhydramine has been tested in a randomized, double-blind, triple crossover, 8-week trial in 38 adults with spinal cord injuries [18]. Maximum daily doses were 2600 mg for gabapentin and 150 mg for amitriptyline.

Amitriptyline was more efficacious in relieving neuropathic pain than diphenhydramine. Withdrawal because of possible adverse reactions occurred five times during gabapentin treatment:

(1) shortness of breath;

(2) dizziness, fatigue, and nausea;

(3) increased spasticity and pain;

(4) fatigue, drowsiness, constipation, and dry mouth; and

(5) severe itching.

The four most frequent adverse events were dry mouth, drowsiness, fatigue, and constipation, which were all more common with amitriptyline.

Gabapentin is Used to Treat Seizures and Postherpetic Neuralgia ?

What is gabapentin?

Gabapentin is a prescription drug. It comes as an oral capsule, an immediate-release oral tablet, an extended-release oral tablet, and an oral solution.

Gabapentin oral capsule is available as the brand-name drug Neurontin. It’s also available as a generic drug. Generic drugs usually cost less than the brand-name version. In some cases, the brand-name drug and the generic version may be available in different forms and strengths.

Why it’s used

Currently, gabapentin has FDA approval for:

- Postherpetic neuralgia
- Adjunctive therapy in the treatment of partial seizures with or without secondary generalization in patients over the age of 12 years old with epilepsy, and the pediatric population, 3 to 12 year-olds with a partial seizure
- Moderate to severe restless leg syndrome (RLS) moderate to severe

It also has off-label use for neuropathic pain, fibromyalgia, bipolar disorder, postmenopausal hot flashes, essential tremors, anxiety, resistant depressant and mood disorders, irritable bowel syndrome (IBS), alcohol withdrawal, postoperative analgesia, nausea and vomiting, migraine prophylaxis, headache, interstitial cystitis, painful diabetic neuropathy, social phobia, generalized tonic-clonic seizures, pruritus (itching), insomnia, post-traumatic stress disorder (PTSD), and refractory chronic cough.

Gabapentin oral capsule is used to treat the following conditions:

- Seizures: Gabapentin is used to treat partial (focal) seizures. It’s taken together with other seizure medications in adults and in children 3 years of age and older who have epilepsy.
- Postherpetic neuralgia: This is pain from nerve damage caused by shingles, a painful rash that affects adults. Shingles appears after infection with the varicella zoster virus. This virus occurs in people who have had chicken pox.

Nerve pain can be a symptom of many different conditions, including cancer, HIV, diabetes, and shingles. For some, nerve pain is frustrating; for others, nerve pain is devastating and life-changing.

Whether it feels like burning, pinpricks, or sudden shocks of electricity, nerve pain can disrupt your life at home and at work. It can limit your ability to get around. Over time, it can grind you down. Studies show that people with nerve pain have higher rates of sleep problems,anxiety, and depression.Your nervous system is involved in everything your body does, from regulating your breathing to controlling your muscles and sensing heat and cold.

There are three types of nerves in the body:

1. Autonomic nerves. These nerves control the involuntary or partially voluntary activities of your body, including heart rate, blood pressure, digestion, and temperature regulation.
2. Motor nerves. These nerves control your movements and actions by passing information from your brain and spinal cord to your muscles.
3. Sensory nerves. These nerves relay information from your skin and muscles back to your spinal cord and brain. The information is then processed to let you feel pain and other sensations.

Because nerves are essential to all you do, nerve pain and damage can seriously affect your quality of life.

When you have a serious medical condition such as cancer or HIV, dealing with the additional misery of nerve pain can be especially hard. But there is good news. While nerve pain can’t always be cured, it can be treated — and there are a lot of good options available.

Experts believe that 40 million Americans are living with nerve pain. The impact of nerve pain is tremendous. Both the costs to the healthcare system as well as loss of wages and productivity are staggering.

What is Postherpetic Neuralgia ?

Postherpetic neuralgia (post-hur-PET-ik noo-RAL-juh) is the most common complication of shingles. The condition affects nerve fibers and skin, causing burning pain that lasts long after the rash and blisters of shingles disappear.

The chickenpox (herpes zoster) virus causes shingles. The risk of postherpetic neuralgia increases with age, primarily affecting people older than 60. There’s no cure, but treatments can ease symptoms. For most people, postherpetic neuralgia improves over time.

How Are Nerve Pain and Nerve Damage Treated?

In many instances, nerve damage cannot be cured entirely. But there are various treatments that can reduce your symptoms. Because nerve damage is often progressive, it is important to consult with a doctor when you first notice symptoms. That way you can reduce the likelihood of permanent damage.

Often, the first goal of treatment is to address the underlying condition that’s causing your nerve pain or nerve damage. This may mean:

- Regulating blood sugar levels for people with diabetes
- Correcting nutritional deficiencies
- Changing medications when drugs are causing nerve damage
- Physical therapy or surgery to address compression or trauma to nerves
- Medications to treat autoimmune conditions

Additionally, your doctor may prescribe medications aimed at minimizing the nerve pain you are feeling. These may include:

- Pain relievers
- Tricyclic antidepressants
- Certain anti-seizure drugs – Gabapentin

Complementary and alternative approaches may also help alleviate your nerve pain and discomfort. These include:

- Acupuncture
- Biofeedback
- Hypnosis
- Meditation

Dosage for postherpetic neuralgia

Adult dosage (ages 18–64 years)

- Typical starting dosage: Day 1, 300 mg; day 2, 600 mg (300 mg two times per day, spaced evenly throughout the day); day 3, 900 mg (300 mg, three times per day, spaced evenly throughout the day). Your doctor may further increase your dosage after day 3.
- Maximum dosage: 1,800 mg per day (600 mg, three times per day, spaced evenly throughout the day)

Child dosage (ages 0–17 years)

Dosage for people younger than 18 years has not been established.

Senior dosage (ages 65 years and older)

Your kidney function may decrease with age. Your body may get rid of this drug more slowly. Your doctor may start you on a lower dose so that too much of this drug does not build up in your body. Too much of the drug in your body can be dangerous. Your doctor may change your dose based on how well your kidneys are working.

Gabapentin in Non-Epilepsy Neuropathic Pain like Postherpetic Neuralgia

The FDA approved gabapentin for the management of postherpetic neuralgia in adults. Recently, gabapentin underwent systemic evaluation in the management of diabetic neuropathy. In 1998, Rowbotham and his research team concluded that in 229 postherpetic neuralgia patients, gabapentin had more significant pain reduction as early as two weeks after initiating the treatment.

Furthermore, other measurements of mood, depression, anger-hostility, fatigue, and physical functioning, were more effectively managed with gabapentin compared to placebo.

During the same time, Backonja reviewed the effect of gabapentin in 165 diabetic neuropathy patients and showed the result that pain reduction in the gabapentin group is greater (as measured with an 11-point Likert scale) in comparison to the placebo group. And the results were significant from 2 weeks of initiation of therapy and stayed significant during the eight weeks of study.

Patients in the treatment group also reported improvement in their quality of life. This medication was well tolerated in 67% of patients who received a maximum daily dosage of 3600 mg.

Treatment for Postherpetic neuralgia

Postherpetic neuralgia is a nerve disease occurs after an attack of herpes zoster infection. Herpes zoster or ‘shingles’ is a viral infection which affects the skin, especially sides of the chest, caused by varicella zoster virus. This is the same virus which causes chicken pox in children.

After an episode of herpes, the virus remains dormant in the nerve tissues of the body. This virus may become active when the immunity of the individual reduces or during convalescence after a major illness, resulting in blisters on the skin, known as shingles. It is accompanied with a rash which disappears without major consequences in about two to four weeks. Around 50% of individuals with shingles go on to develop post herpetic neuralgia (PHN) or after-shingles pain.

The neuralgia begins when the herpetic eruptions begin to heal. The pain appears usually in the affected dermatone or the affected nerve course and results in severe pain in the region which has the same nerve supply. The pain is a drawing, pricking type of intense pain, sometimes accompanied with burning sensation of the skin. The pain lasts from a few weeks to few months, rarely years.

Causes

- - Severe rash within three days of shingles infection
  - A study shows that, 65% of patients were women
  - The chances of developing PHN, increases when the shingles occurs in persons over 50 years.
  - The incidence of herpes zoster is up to 15 times higher in HIV-infected patients than in uninfected persons, and as many as 25 percent of patients with Hodgkin’s lymphoma develop herpes zoster.
  - Blacks are one fourth as likely as whites to develop this condition.
  - Site of HZ involvement
    - Lower risk – Jaw, neck, sacral, and lumbar
    - Moderate risk – Thoracic
    - Highest risk – Trigeminal (especially ophthalmic division), brachial plexus.

Signs and symptoms:

- A pain that continues for 3 months or more, after the healing of shingles, is defined as PHN.
- PHN pain may be burning, aching, itching and sharp and the pain can be constant or it can come and go
- The skin which was affected with blisters, may show scarring
- The involved dermatome may show altered sensations, either hypersensitivity or reduced sensitivity.
- In rare cases, where if the nerves involved also control muscle movement, the patient might also experience muscle weakness, tremor or paralysis

Postherpetic Neuralgia Treatment:

The conventional treatment is directed at pain control while waiting for the condition to resolve. Pain therapy may include multiple interventions, such as topical medications, over-the-counter analgesics, tricyclic antidepressants, anticonvulsants and a number of non medical modalities. Occasionally, narcotics may be required.

When it comes to treating postherpetic neuralgia, you may need to take a combination of medications to effectively manage your pain and other PHN symptoms. No single treatment plan is right for everyone—what medications you take will depend on your PHN symptoms.

While symptoms differ from person to person, for most people, PHN does improve over time. Researchers found that more than half of all patients with PHN stop experiencing pain within one year.¹

Fortunately, during that period of intense pain and other symptoms, there are certain medications that you can take to significantly help control postherpetic neuralgia symptoms.

Before trying a prescription medication, your doctor will most likely want you to try an over-the counter (OTC) analgesic (painkiller) medication, such as acetaminophen or non-steroidal anti-inflammatory drugs (NSAIDs). These medications can help relieve pain and other PHN symptoms.

Tylenol is an example of acetaminophen, and Advil is an example of an NSAID you can take to help treat PHN.

Another OTC medication you may want to try for PHN is capsaicin cream. This cream—made from hot chili pepper seeds—is applied to the affected skin, and it can be helpful for reducing PHN-related pain. But this cream can be painful, so talk to your doctor about how much you should apply.

If these medications aren’t strong enough to treat your PHN symptoms, your doctor may suggest some of the prescription medications below to treat your postherpetic neuralgia.

- Tricyclic antidepressants, such as amitriptyline (Elavil), nortriptyline (Pamelor), and desipramine (Norpramin) are effective at treating postherpetic neuralgia pain. Other classes of antidepressant are also helpful. All classes of antidepressant take a few weeks to start working.
- Anticonvulsants, developed to control seizures, can help reduce the pain of PHN. These include gabapentin (Neurontin), carbamazepine (Tegretol) and pregabalin (Lyrica). Gabapentin enacarbil (Horizant) and gabapentin (Gralise) are approved by the FDA for the treatment of PHN in adults.
- Anti-viral drugs valacyclovir and acyclovir are also becoming medications of choice for treating postherpetic neuralgia.
- Lidocaine Patches for Postherpetic Neuralgia. Lidocaine patches are FDA-approved to treat PHN. The medication in the patch—lidocaine—can penetrate your skin and go to the nerves that are sending the pain signals. A benefit of lidocaine patches is that they don’t numb the skin.
- Prescription capsaicin patches. These patches contain a very high concentration of the chili pepper extract capsaicin. The capsaicin patch Qutenza is applied in a doctor’s office for one hour every three months.

If you have severe pain and other medications don’t work for you, your doctor may want you to try an opioid. Tramadol (eg, Ultram) is an example of a relatively weak opioid that can be used to help you manage PHN. Your doctor may have you try a weaker opioid first. Opioids, such as morphine (MS Contin), oxycodone (OxyContin), and hydrocodone (Vidocin), are also used to treat moderate to severe pain of postherpetic neuralgia.

Homoeopathic Medicine:

Mezereum – For Postherpetic Neuralgia with Intense Burning

Mezereum is rated among the best medicines for postherpetic neuralgia. It is the best-suited prescription when postherpetic neuralgic pains are violent and attended with marked burning. Mezereum is the most helpful among medicines for postherpetic neuralgia in postherpetic pains located in the face. The pain in the face may get worse while eating.

Warmth brings relief. Mezereum is also helpful during active herpes zoster where eruptions are present. The key symptoms to look out for before prescribing Mezereum during herpes zoster infection are violently itching vesicles with shining red areola and intense burning.

2. Ranunculus Bulbosus – For Pains coming in Paroxysms

Another of the prominently indicated medicines for postherpetic neuralgia is Ranunculus Bulbosus. It is indicated for sharp, shooting, postherpetic neuralgic pains that come in paroxysms.

It is also one of the top listed medicines for intercostal neuralgia following herpetic infection. Ranunculus Bulbosus is also indicated for herpes zoster when the vesicles eruptions are bluish in colour. The eruptions are attended with itching and burning symptoms which worsen on contact.

3. Rhus Tox – One of the best Medicines for Postherpetic Neuralgia

Rhus Tox also figures on the list of highly effective medicines for postherpetic neuralgia. It is one of the best medicines for postherpetic neuralgia where the pains are attended with marked restlessness. The skin is sensitive to cold air in such cases. In herpes zoster, Rhus Tox is the most preferred among medicines when the vesicles are yellowish with itching and stinging.

Does Gabapentin Cause Constipation?

Gabapentin may cause constipation, but it is not a common side effect. In clinical trials of adults taking gabapentin for nerve pain, only about 4% of people reported constipation.

Gabapentin belongs to a class of drugs called anticonvulsants. A class of drugs is a group of medications that work in a similar way. These drugs are often used to treat similar conditions.

It’s not fully understood how gabapentin works. For postherpetic neuralgia, it seems to prevent the increase in sensitivity to pain that occurs. For seizures, it may alter the effect of calcium (low levels of calcium may cause seizures).

Who may not be able to take gabapentin

Gabapentin is not suitable for some people.

To make sure it’s safe for you, tell your doctor if you:

- have ever had an allergic reaction to gabapentin or any other medicine
- have ever misused or been addicted to a medicine
- are trying to get pregnant or are already pregnant
- are on a controlled sodium or potassium diet, or your kidneys do not work well (gabapentin liquid contains sodium and potassium, so speak to your doctor before taking it)

Some people in these trials took an inactive medicine (placebo). About 2% of people taking a placebo also reported constipation, so the actual percentage of people with constipation while taking gabapentin is probably less than 4%.

In clinical trials of people aged 12 and over taking gabapentin for seizure disorder, about 2% reported constipation as a side effect. Out of people taking a placebo, 1% also reported constipation.

In the clinical trials of gabapentin to treat nerve pain in adults, the most common side effects were:

Dizziness
Sleepiness
Swelling in the hands or feet (peripheral edema)

In clinical trials of people older than 12 taking gabapentin to treat a seizure disorder, the most common side effects were sleepiness and clumsiness (ataxia).

Thoughts of death or suicide is another rare but important side effect of gabapentin, occurring in about 1 in 500 people. These thoughts can happen within one week of starting gabapentin. Call your doctor right away if you have any unusual changes in mood or behavior, or any of these symptoms:

Thoughts about suicide or dying
Suicide attempt
Depression, new or worsening
Anxiety, new or worsening
Panic attacks

In 2019, the U.S. Food and Drug Administration (FDA) added another important warning about gabapentin: When this drug is taken with opioid pain medication or used by a person with chronic lung disease like chronic obstructive pulmonary disease (COPD), it may cause severe and possibly fatal difficulty breathing (respiratory depression). Before starting gabapentin, let your doctor know if you are taking any opioid drug, or if you have been diagnosed with a lung disease.

Even if you have side effects from gabapentin, it is important not to stop taking it suddenly on your own. This medication must be reduced over time (tapered) by your doctor. Stopping suddenly can lead to withdrawal symptoms such as:

Anxiety
Insomnia
Nausea
Pain

If you are taking gabapentin to control seizures, stopping suddenly may increase your risk of a seizure.

What is the most important information I should know about Gabapentin ( NEURONTIN )?

Do not stop taking NEURONTIN without first talking to your healthcare provider. Stopping NEURONTIN suddenly can cause serious problems.

Before taking gabapentin,

tell your doctor and pharmacist if you are allergic to gabapentin, any other medications, or any of the inactive ingredients in the type of gabapentin you plan to take. Ask your pharmacist for a list of the inactive ingredients.
you should know that gabapentin is available in different forms that may be prescribed for different uses. Ask your doctor to be sure that you are not taking more than one product that contains gabapentin.
tell your doctor and pharmacist what prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take. Be sure to mention any of the following: antidepressants; antihistamines; medications for anxiety; medications that make you feel dizzy or drowsy; medications for mental illness; naproxen (Aleve, Anaprox, Naprosyn, others); opioid (narcotic) medications for pain such as hydrocodone (in Hydrocet, in Vicodin, others), morphine (Avinza, Kadian, MSIR, others), or oxycodone OxyContin, in Percocet, in Roxicet, others); sedatives; medications for seizures; sleeping pills, and tranquilizers. Your doctor may need to change the doses of your medications or monitor you carefully for side effects.
if you are taking antacids such as Maalox or Mylanta, take them at least 2 hours before you take gabapentin tablets, capsules, or solution.
tell your doctor if you have or have ever had lung or kidney disease. If you will be taking the extended-release tablets, also tell your doctor if you need to sleep during the day and stay awake at night.
tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. If you become pregnant while taking gabapentin, call your doctor.
if you are having surgery, including dental surgery, tell the doctor or dentist that you are taking gabapentin.
you should know that this medication may make you drowsy or dizzy, may slow your thinking, and may cause loss of coordination. Do not drive a car or operate machinery until you know how this medication affects you, and your doctor agrees that it is safe for you to begin these activities.
if you are giving gabapentin to your child, you should know that your child’s behavior and mental abilities may change while he or she is taking gabapentin. Your child may have sudden changes in mood, become hostile or hyperactive, have difficulty concentrating or paying attention, or be drowsy or clumsy. Have your child avoid activities that could be dangerous, such as riding a bicycle, until you know how gabapentin affects him or her.
remember that alcohol can add to the drowsiness caused by this medication.
you should know that your mental health may change in unexpected ways and you may become suicidal (thinking about harming or killing yourself or planning or trying to do so) while you are taking gabapentin for the treatment of epilepsy, mental illness, or other conditions. A small number of adults and children 5 years of age and older (about 1 in 500 people) who took anticonvulsants such as gabapentin to treat various conditions during clinical studies became suicidal during their treatment. Some of these people developed suicidal thoughts and behavior as early as one week after they started taking the medication. There is a risk that you may experience changes in your mental health if you take an anticonvulsant medication such as gabapentin, but there may also be a risk that you will experience changes in your mental health if your condition is not treated. You and your doctor will decide whether the risks of taking an anticonvulsant medication are greater than the risks of not taking the medication. You, your family, or your caregiver should call your doctor right away if you experience any of the following symptoms: panic attacks; agitation or restlessness; new or worsening irritability, anxiety, or depression; acting on dangerous impulses; difficulty falling or staying asleep; aggressive, angry, or violent behavior; mania (frenzied, abnormally excited mood); talking or thinking about wanting to hurt yourself or end your life; withdrawing from friends and family; preoccupation with death and dying; giving away prized possessions; or any other unusual changes in behavior or mood. Be sure that your family or caregiver knows which symptoms may be serious so they can call the doctor if you are unable to seek treatment on your own.

NEURONTIN can cause serious side effects including:

1. Suicidal Thoughts. Like other antiepileptic drugs, NEURONTIN may cause suicidal thoughts or actions in a very small number of people, about 1 in 500.

Call a healthcare provider right away if you have any of these symptoms, especially if they are new, worse, or worry you:

- - thoughts about suicide or dying
  - attempts to commit suicide
  - new or worse depression
  - new or worse anxiety
  - feeling agitated or restless
  - panic attacks
  - trouble sleeping (insomnia)
  - new or worse irritability
  - acting aggressive, being angry, or violent
  - acting on dangerous impulses
  - an extreme increase in activity and talking (mania)
  - other unusual changes in behavior or mood

How can I watch for early symptoms of suicidal thoughts and actions?

- - Pay attention to any changes, especially sudden changes, in mood, behaviors, thoughts, or feelings.
  - Keep all follow-up visits with your healthcare provider as scheduled.

Call your healthcare provider between visits as needed, especially if you are worried about symptoms.

Do not stop taking NEURONTIN without first talking to a healthcare provider.

- - Stopping NEURONTIN suddenly can cause serious problems. Stopping a seizure medicine suddenly in a patient who has epilepsy can cause seizures that will not stop (status epilepticus).
  - Suicidal thoughts or actions can be caused by things other than medicines. If you have suicidal thoughts or actions, your healthcare provider may check for other causes.

2. Changes in behavior and thinking –Using NEURONTIN in children 3 to 12 years of age can cause emotional changes, aggressive behavior, problems with concentration, restlessness, changes in school performance, and hyperactivity.

3. NEURONTIN may cause serious or life-threatening allergic reactions that may affect your skin or other parts of your body such as your liver or blood cells.

This may cause you to be hospitalized or to stop NEURONTIN. You may or may not have a rash with an allergic reaction caused by NEURONTIN. Call a healthcare provider right away if you have any of the following symptoms:

- - skin rash
  - hives
  - difficulty breathing
  - fever
  - swollen glands that do not go away
  - swelling of your face, lips, throat, or tongue
  - yellowing of your skin or of the whites of the eyes
  - unusual bruising or bleeding
  - severe fatigue or weakness
  - unexpected muscle pain
  - frequent infections

These symptoms may be the first signs of a serious reaction. A healthcare provider should examine you to decide if you should continue taking NEURONTIN.

Before taking gabapentin,

tell your doctor and pharmacist if you are allergic to gabapentin, any other medications, or any of the inactive ingredients in the type of gabapentin you plan to take. Ask your pharmacist for a list of the inactive ingredients.
you should know that gabapentin is available in different forms that may be prescribed for different uses. Ask your doctor to be sure that you are not taking more than one product that contains gabapentin.
tell your doctor and pharmacist what prescription and nonprescription medications, vitamins, nutritional supplements, and herbal products you are taking or plan to take. Be sure to mention any of the following: hydrocodone (in Hydrocet, in Vicodin, others), medications that make you feel dizzy or drowsy, morphine (Avinza, Kadian, MSIR, others), and naproxen (Aleve, Anaprox, Naprosyn, others). Your doctor may need to change the doses of your medications or monitor you carefully for side effects.
if you are taking antacids such as Maalox or Mylanta, take them at least 2 hours before you take gabapentin tablets, capsules, or solution.
tell your doctor if you have or have ever had kidney disease. If you will be taking the extended-release tablets, also tell your doctor if you need to sleep during the day and stay awake at night.
tell your doctor if you are pregnant, plan to become pregnant, or are breast-feeding. If you become pregnant while taking gabapentin, call your doctor.
if you are having surgery, including dental surgery, tell the doctor or dentist that you are taking gabapentin.
you should know that this medication may make you drowsy or dizzy, may slow your thinking, and may cause loss of coordination. Do not drive a car or operate machinery until you know how this medication affects you, and your doctor agrees that it is safe for you to begin these activities.
if you are giving gabapentin to your child, you should know that your child’s behavior and mental abilities may change while he or she is taking gabapentin. Your child may have sudden changes in mood, become hostile or hyperactive, have difficulty concentrating or paying attention, or be drowsy or clumsy. Have your child avoid activities that could be dangerous, such as riding a bicycle, until you know how gabapentin affects him or her.
remember that alcohol can add to the drowsiness caused by this medication.
you should know that your mental health may change in unexpected ways and you may become suicidal (thinking about harming or killing yourself or planning or trying to do so) while you are taking gabapentin for the treatment of epilepsy, mental illness, or other conditions. A small number of adults and children 5 years of age and older (about 1 in 500 people) who took anticonvulsants such as gabapentin to treat various conditions during clinical studies became suicidal during their treatment. Some of these people developed suicidal thoughts and behavior as early as one week after they started taking the medication. There is a risk that you may experience changes in your mental health if you take an anticonvulsant medication such as gabapentin, but there may also be a risk that you will experience changes in your mental health if your condition is not treated. You and your doctor will decide whether the risks of taking an anticonvulsant medication are greater than the risks of not taking the medication. You, your family, or your caregiver should call your doctor right away if you experience any of the following symptoms: panic attacks; agitation or restlessness; new or worsening irritability, anxiety, or depression; acting on dangerous impulses; difficulty falling or staying asleep; aggressive, angry, or violent behavior; mania (frenzied, abnormally excited mood); talking or thinking about wanting to hurt yourself or end your life; withdrawing from friends and family; preoccupation with death and dying; giving away prized possessions; or any other unusual changes in behavior or mood. Be sure that your family or caregiver knows which symptoms may be serious so they can call the doctor if you are unable to seek treatment on your own.

Gabapentin warnings

Gabapentin oral capsule comes with several warnings. Call your doctor if you start having more seizures or a different kind of seizure while taking this drug.

Drowsiness warning

Gabapentin can slow your thinking and motor skills and cause drowsiness and dizziness. It’s not known how long these effects last. You should not drive or use heavy machinery while taking this drug until you know how it affects you.

Depression warning

Using this drug increases your risk of suicidal thoughts and behavior. Talk to your doctor if you feel depressed or notice any changes in your mood or behavior. Also talk to your doctor if you are having thoughts of harming yourself, including suicide.

Multiorgan hypersensitivity/DRESS warning

This medication can cause multiorgan hypersensitivity. This is also known as a drug reaction with eosinophilia and systemic symptoms (DRESS). This syndrome can be life-threatening. Call your doctor right away if you have symptoms such as a rash, a fever, or swollen lymph nodes.

Allergy warning

Gabapentin can cause a severe allergic reaction. Symptoms can include:

trouble breathing
swelling of your throat or tongue
hives
rash

Don’t take this drug again if you have ever had an allergic reaction to it before. Taking it a second time after any allergic reaction to it could be fatal (cause death).

Alcohol interaction warning

Avoid drinking alcohol while taking gabapentin. Gabapentin can cause sleepiness, and drinking alcohol can make you even more sleepy. Alcohol can also make you more likely to feel dizzy and have trouble concentrating.

Warnings for people with certain health conditions

For people with epilepsy: Don’t stop taking gabapentin suddenly. Doing this can increase your risk of having a condition called status epilepticus. This is a medical emergency during which short or long seizures occur for 30 minutes or more.

Gabapentin can cause problems in children aged 3–12 years who have epilepsy. It raises their risk of thought problems as well as behavioral problems, such as being hyper and acting hostile or restless.

For people with kidney problems: Your body processes this drug more slowly than normal. This may cause the drug to increase to dangerous levels in your body. Talk to your doctor about whether this drug is safe for you.

Warnings for other groups

For pregnant women: The use of gabapentin has not been studied in humans during pregnancy. Research in animals has shown negative effects to the fetus when the mother takes the drug. However, animal studies don’t always predict the way humans would respond.

Talk to your doctor if you’re pregnant or planning to become pregnant. This drug should only be used if the potential benefit justifies the potential risk to the fetus. Call your doctor if you become pregnant while taking this drug.

If your doctor prescribes gabapentin for you while you’re pregnant, ask about the NAAED Pregnancy Registry. This registry tracks the effects of anti-seizure drugs on pregnancy. Information can be found at aedpregnancyregistry.org.

For women who are breastfeeding: Gabapentin may pass into breast milk and cause serious side effects in a breastfeeding child. Tell your doctor if you are breastfeeding. You should decide together if you should stop taking this drug or stop breastfeeding.

For seniors: Kidney function may decrease with age. You may process this drug more slowly than younger people. Your doctor may start you on a lowered dose so that too much of this drug does not build up in your body. Too much of the drug in your body can be dangerous.

For children: Gabapentin has not been studied in children for the management of postherpetic neuralgia. It should not be used in people younger than 18 years. This drug should not be used to treat partial seizures in children younger than 3 years.

What is the Common Side Effects of Gabapentin in Children ?

We donot suggest children take online gabapentin prescription. Please order Gabapentin from your local street Gabapentin pharmacy.

The More common Side Effects in children:

Aggressive behavior or other behavior problems
anxiety
concentration problems and change in school performance
crying
depression
false sense of well-being
hyperactivity or increase in body movements
rapidly changing moods
reacting too quickly, too emotional, or overreacting
restlessness
suspiciousness or distrust

Less Common

Black, tarry stools
chest pain
chills
cough
depression, irritability, or other mood or mental changes
fever
loss of memory
pain or swelling in the arms or legs
painful or difficult urination
shortness of breath
sore throat
sores, ulcers, or white spots on the lips or in the mouth
swollen glands
unusual bleeding or bruising
unusual tiredness or weakness

What are the possible side effects of Gabapentin (Gralise, Horizant, Neurontin)?

Get emergency medical help if you have any of these signs of an allergic reaction: hives; fever; swollen glands; painful sores in or around your eyes or mouth; difficulty breathing; swelling of your face, lips, tongue, or throat.

Report any new or worsening symptoms to your doctor, such as: mood or behavior changes, anxiety, depression, or if you feel agitated, hostile, restless, hyperactive (mentally or physically), or have thoughts about suicide or hurting yourself.

Call your doctor at once if you have a serious side effect such as:

increased seizures;
fever, swollen glands, body aches, flu symptoms;
skin rash, easy bruising or bleeding, severe tingling, numbness, pain, muscle weakness;
upper stomach pain, loss of appetite, dark urine, jaundice (yellowing of the skin or eyes);
chest pain, irregular heart rhythm, feeling short of breath;
confusion, nausea and vomiting, swelling, rapid weight gain, urinating less than usual or not at all;
new or worsening cough, fever, trouble breathing; or
rapid back and forth movement of your eyes.

Some side effects are more likely in children taking gabapentin.

Contact your doctor if the child taking this medication has any of the following side effects:

changes in behavior;
memory problems;
trouble concentrating; or
acting restless, hostile, or aggressive.

Less serious side effects of Neurontin® may include:

dizziness, drowsiness, weakness, tired feeling;
nausea, diarrhea, constipation;
blurred vision;
headache;
breast swelling;
dry mouth; or
loss of balance or coordination.

This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.

Individual Factors That Also Increase Risk

Several other factors also play a significant role in your likelihood of side effects. Some notable examples include:

Genetics: Pharmacogenetics is the name given to the study of how your genes influence your reaction to drugs and genetic factors account for 20-95% of patient variability. This field of pharmacology is rapidly evolving and testing for liver enzyme variations becoming more widespread. For example, codeine requires metabolism through CYP2D6 for conversion to one of its active metabolites, morphine. 5-10% of patients are poor metabolizers – which means that very little codeine is converted to morphine which results in insufficient pain relief. However, 1-2% of people are ultra-rapid metabolizers and more codeine is converted into morphine than normal, resulting in a higher risk of toxic reactions including respiratory depression
Kidney function If your kidneys are not functioning at full capacity, then side effects are more likely if you are taking drugs that are excreted through the kidneys. Some other drugs also cease to be effective when kidney function is reduced.
Gender: Females have a lower activity of certain hepatic enzymes, a higher body fat to water ratio, and a decreased clearance of drugs through the kidneys than men. Studies have shown the incidence of drug-induced liver toxicity, gastrointestinal side effects, allergic skin reactions, and long QT syndrome is higher in females.

Applies to gabapentin: oral capsule, oral solution, oral suspension, oral tablet

Along with its needed effects, gabapentin (the active ingredient contained in Neurontin) may cause some unwanted effects. Although not all of these side effects may occur, if they do occur they may need medical attention.

Check with your doctor immediately if any of the following side effects occur while taking gabapentin:

More Common

Clumsiness or unsteadiness
continuous, uncontrolled, back-and-forth, or rolling eye movements

More common in children

Aggressive behavior or other behavior problems
anxiety
concentration problems and change in school performance
crying
depression
false sense of well-being
hyperactivity or increase in body movements
rapidly changing moods
reacting too quickly, too emotional, or overreacting
restlessness
suspiciousness or distrust

Less Common

Black, tarry stools
chest pain
chills
cough
depression, irritability, or other mood or mental changes
fever
loss of memory
pain or swelling in the arms or legs
painful or difficult urination
shortness of breath
sore throat
sores, ulcers, or white spots on the lips or in the mouth
swollen glands
unusual bleeding or bruising
unusual tiredness or weakness

Incidence Not Known

Abdominal or stomach pain
blistering, peeling, or loosening of the skin
clay-colored stools
coma
confusion
convulsions
dark urine
decreased urine output
diarrhea
dizziness
fast or irregular heartbeat
headache
increased thirst
itching or skin rash
joint pain
large, hive-like swelling on the face, eyelids, lips, tongue, throat, hands, legs, feet, or sex organs
loss of appetite
muscle ache or pain
nausea
red skin lesions, often with a purple center
red, irritated eyes
unpleasant breath odor
vomiting of blood
yellow eyes or skin

Some side effects of gabapentin may occur that usually do not need medical attention. These side effects may go away during treatment as your body adjusts to the medicine. Also, your health care professional may be able to tell you about ways to prevent or reduce some of these side effects. Check with your health care professional if any of the following side effects continue or are bothersome or if you have any questions about them:

More Common

Blurred vision
cold or flu-like symptoms
delusions
dementia
hoarseness
lack or loss of strength
lower back or side pain
swelling of the hands, feet, or lower legs
trembling or shaking

Less Common or Rare

Accidental injury
appetite increased
back pain
bloated or full feeling
body aches or pain
burning, dry, or itching eyes
change in vision
change in walking and balance
clumsiness or unsteadiness
congestion
constipation
cough producing mucus
decrease in sexual desire or ability
difficulty with breathing
dryness of the mouth or throat
earache
excess air or gas in the stomach or intestines
excessive tearing
eye discharge
feeling faint, dizzy, or lightheadedness
feeling of warmth or heat
flushed, dry skin
flushing or redness of the skin, especially on the face and neck
frequent urination
fruit-like breath odor
impaired vision
incoordination
increased hunger
increased sensitivity to pain
increased sensitivity to touch
increased thirst
indigestion
noise in the ears
pain, redness, rash, swelling, or bleeding where the skin is rubbed off
passing gas
redness or swelling in the ear
redness, pain, swelling of the eye, eyelid, or inner lining of the eyelid
runny nose
sneezing
sweating
tender, swollen glands in the neck
tightness in the chest
tingling in the hands and feet
trouble sleeping
trouble swallowing
trouble thinking
twitching
unexplained weight loss
voice changes
vomiting
weakness or loss of strength
weight gain

What are the Precautions When Taking Gabapentin (Neurontin®)?

Gabapentin (brand name: Neurontin) is a generic prescription drug that is FDA-approved as an add-on treatment with other medications for partial seizures in those with epilepsy. It can also be used to treat nerve pain from postherpetic neuralgia (a complication of shingles). Gabapentin is frequently prescribed off-label for many other conditions, such as diabetic peripheral neuropathy, fibromyalgia, and alcohol dependence.

Gabapentin is an anticonvulsive medication that originally saw use as a muscle relaxer and anti-spasmodic medication, but later it was discovered it had the potential of the medication as anticonvulsive medication and as an adjunct to more potent anticonvulsants. It is also useful in certain types of neural pain control. This activity outlines the indications, mechanism of action, dosing, significant adverse effects, contraindications, monitoring, and toxicity of gabapentin and increases practitioners’ knowledge about how to approach this medication and all health professionals in how to monitor it to drive better patient outcomes.

Gabapentin is typically prescribed as a generic, but the drug is also available under the brand names Neurontin and Gralise. Some patients may be prescribed drugs very similar to gabapentin—such as Horizant (gabapentin enacarbil) or Lyrica (pregabalin)—instead of gabapentin.

Gabapentin is taken as a tablet, capsule, or oral liquid. Dosing will depend on the condition being treated, age of the person being treated, and kidney function. The usual dose for epilepsy starts at 300 mg on the first day. The dose can then be increased until an effective dose is reached, which is usually 300 to 600mg taken three times per day.

Forms and Strengths

Generic: Gabapentin

- Form: oral capsule
- Strengths: 100 mg, 300 mg, 400 mg

Brand: Neurontin

- Form: oral capsule
- Strengths: 100 mg, 300 mg, 400 mg

Dosage for postherpetic neuralgia

Adult dosage (ages 18–64 years)

Typical starting dosage: Day 1, 300 mg; day 2, 600 mg (300 mg two times per day, spaced evenly throughout the day); day 3, 900 mg (300 mg, three times per day, spaced evenly throughout the day). Your doctor may further increase your dosage after day 3.
Maximum dosage: 1,800 mg per day (600 mg, three times per day, spaced evenly throughout the day)

Child dosage (ages 0–17 years)

Dosage for people younger than 18 years has not been established.

Senior dosage (ages 65 years and older)

This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.

Before using Gabapentin (buy neurontin® online), tell your doctor or pharmacist your medical history, especially of: kidney disease, mental/mood problems (such as depression, thoughts of suicide), use/abuse of drugs/alcohol.

This drug may make you dizzy or drowsy or cause blurred vision. Do not drive, use machinery, or do any activity that requires alertness or clear vision until you are sure you can perform such activities safely. Limit alcoholic beverages.

Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).

Older adults may be more sensitive to the side effects of this drug, especially swelling of the hands/ankles/feet, dizziness, or loss of coordination. Dizziness and loss of coordination can increase the risk of falling.

Children may be more sensitive to the side effects of this drug, especially mental/mood/behavior changes (such as hostility, problems concentrating, restlessness).

During pregnancy, this medication should be used only when clearly needed. Discuss the risks and benefits with your doctor.

Gabapentin passes into breast milk. Consult your doctor before breast-feeding.

Gabapentin OVERDOSE

A lethal dose of gabapentin was not identified in mice and rats receiving single oral doses as high as 8000 mg/kg. Signs of acute toxicity in animals included ataxia, labored breathing, ptosis, sedation, hypoactivity, or excitation.

Acute oral overdoses of NEURONTIN up to 49 grams have been reported. In these cases, double vision, slurred speech, drowsiness, lethargy, and diarrhea were observed. All patients recovered with supportive care. Coma, resolving with dialysis, has been reported in patients with chronic renal failure who were treated with NEURONTIN.

Gabapentin can be removed by hemodialysis. Although hemodialysis has not been performed in the few overdose cases reported, it may be indicated by the patient’s clinical state or in patients with significant renal impairment.

If overexposure occurs, call your poison control center at 1-800-222-1222.

Gabapentin may interact with other medications

Gabapentin oral capsule can interact with several other medications. Different interactions can cause different effects. For instance, some can interfere with how well a drug works, while others can cause increased side effects.

Below is a list of medications that can interact with gabapentin. This list does not contain all drugs that may interact with gabapentin.

Before taking gabapentin, be sure to tell your doctor and pharmacist about all prescription, over-the-counter, and other drugs you take. Also tell them about any vitamins, herbs, and supplements you use. Sharing this information can help you avoid potential interactions.

If you have questions about drug interactions that may affect you, ask your doctor or pharmacist.

Pain drugs

When used with gabapentin, certain pain drugs can increase its side effects, such as tiredness. Examples of these drugs include:

morphine

Stomach acid drugs

When used with gabapentin, certain drugs used to treat stomach acid problems can reduce the amount of gabapentin in your body. This can make it less effective. Taking gabapentin 2 hours after taking these drugs can help prevent this problem. Examples of these drugs include:

aluminum hydroxide
magnesium hydroxide

Important considerations for taking gabapentin

Keep these considerations in mind if your doctor prescribes gabapentin oral capsule for you.

General

Gabapentin oral capsules can be taken with or without food. Taking them with food can help to reduce upset stomach.

Storage

Store gabapentin at room temperature between 68°F and 77°F (20°C and 25°C).
Don’t store this medication in moist or damp areas, such as bathrooms.

Refills

A prescription for this medication is refillable. You should not need a new prescription for this medication to be refilled. Your doctor will write the number of refills authorized on your prescription.

Travel

When traveling with your medication:

Always carry your medication with you, such as in your carry-on bag.
Don’t worry about airport X-ray machines. They can’t hurt your medication.
You may need to show airport staff the pharmacy label for your medication. Be sure to carry with you the prescription-labeled box that your medication came in.
Do not put this medication in your car’s glove compartment or leave it in the car. Be sure to avoid doing this when the weather is very hot or very cold.

Clinical monitoring

Your doctor will monitor your kidney function.

Insurance

Many insurance companies require a prior authorization for gabapentin. This means your doctor will need to get approval from your insurance company before your insurance company will pay for the prescription.

Are there any alternatives?

There are other drugs available to treat your condition. Some may be better suited for you than others. Talk to your doctor about other drug options that may work for you.

Disclaimer: Healthline has made every effort to make certain that all information is factually correct, comprehensive, and up-to-date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or other healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses.

Online Gabapentin Dosage Information

There are several online Gabapentin Dosage Available.

Gabapentin 800mg 180 tab
Gabapentin 600mg 180 tab
Gabapentin 400mg 180 tab
Gabapentin 300mg 180 tab

Normally Gabapentin 800mg is hard to get from online pharmacy because you have to gradually take gabapentin to solve your berve pain problems.

Gabapentin Dosing Considerations

Three gabapentin products are FDA approved to treat PHN. The different formulations cannot be interchanged and each has its own dosing schedule.

- For immediate-release gabapentin (Neurontin), dosing may be initiated with 300 mg on day 1, doubled on day 2 (300 mg twice a day), and tripled on day 3 (300 mg 3 times a day). The dose can then be titrated up as needed for pain relief to a maximum dose of 1,800 mg daily (divided into 3 daily doses). Clinical studies referenced in the package insert state that efficacy for a range of doses from 1,800 mg/day to 3,600 mg/day were observed; however, there was no additional benefit seen with doses greater than 1,800 mg/d.
- Gralise is an extended-release gabapentin formulation that also is FDA approved for PHN with a titration schedule that begins with 300 mg on day 1; 600 mg on day 2; 900 mg on days 3 to 6; 1,200 mg on days 7 to 10; 1,500 mg on days 11 to 14; and 1,800 mg on day 15 and thereafter.
- The third gabapentin formulation for PHN treatment is another extended-release product, Horizant. The starting dose is 600 mg in the morning for 3 days, increased to 600 mg twice daily on day 4 and thereafter. A daily dose of Horizant greater than 1,200 mg provided no additional benefit at the expense of side effects.

Several studies have evaluated off-label use of gabapentin in the treatment of other neuropathic pain conditions. A randomized, double-blind trial compared gabapentin to placebo in 135 patients with DPN over 8 weeks. The results showed a statistical benefit of gabapentin compared to placebo, at all end points, for pain improvement.⁴ The gabapentin dosing regimen used in this study was 900 mg/d for week 1; 1,800 mg/d for week 2; 2,400 mg/d for week 3; and 3,600 mg/d for week 4. All the patients were titrated up to a dose of 3,600 mg/d, regardless of efficacy at lower doses. Patients who could not tolerate this dose were titrated down to the greatest tolerable dose.

Of the 84 patients randomized to the gabapentin group, 56 (67%) were able to tolerate 3,600 mg/d.⁴During the first week, gabapentin resulted in improvement in sleep interference compared to placebo. By the second week, gabapentin resulted in improvement in all pain rating scales compared to placebo. Of the 84 patients in the gabapentin group, 70 completed the study, and 7 patients withdrew due to adverse drug events (ADEs). Most ADEs reported in the gabapentin group were of mild or moderate intensity, and the most frequently reported effects were dizziness (23.8%), somnolence (22.6%), headache (10.7%), diarrhea (10.7%), confusion (8.3%), and nausea (8.3%).

A double-blind crossover study (n=40) assessed gabapentin for the treatment of DPN. The dose of gabapentin used in this trial was much lower, with patients titrated up every 3 days to a maximum dose of 900 mg/d.

The end points evaluated in this study included level of pain on a visual analog pain scale (VAS), and scores on the present pain intensity scale, the McGill pain questionnaire (MPQ), and the global assessment of pain relief. Statistical improvement between gabapentin and placebo was noted in only 1 end point, the MPQ score, with a mean reduction of 8.9 points for gabapentin compared to 2.2 points with placebo (P=0.03). No serious ADEs were noted, and the most common ADEs of gabapentin were drowsiness, fatigue, and imbalance.

The results of this study suggest that gabapentin is not effective or is only minimally effective in treating painful DPN at a dose of 900 mg/d.⁵

A search in the Cochrane Database of Systematic Reviews was conducted to further examine dosing regimens for neuropathic pain. In a review analyzing 37 studies for gabapentin treatment in chronic neuropathic pain, the main outcome was Initiative on Methods, Measurement, and Pain Assessment in Clinical Trials (IMMPACT) definitions for moderate and substantial benefit in chronic pain studies.⁶ These were defined as follows:

- 30% reduction in pain over baseline (moderate)
- 50% reduction in pain over baseline (substantial)
- Much or very much improved on Patient Global Impression of Change (PGIC) (moderate)
- Very much improved on PGIC (substantial)
- Gabapentin was shown to be better than placebo across all studies for IMMPACT outcomes. The review concentrated on gabapentin doses of 1,200 mg/d or greater and reported that doses at or above this threshold were reasonably effective for treatment of various neuropathic pain types. The upper threshold for maximum effective gabapentin doses ranged from 2,400 mg/d to 3,600 mg/d in the majority of studies reviewed.⁶ Table 1, on page 16, provides a more detailed description of the maximum gabapentin doses evaluated for different neuropathic pain types.

Usual Adult Dose for Postherpetic Neuralgia:

Initial dose: 300 mg orally on day one, 300 mg orally twice a day on day two, then 300 mg orally 3 times a day on day three.

The dose may be titrated up as needed for pain relief to a daily dose of 1800 mg. Maintenance dose: 900 to 1800 mg orally in 3 divided doses.

Efficacy was demonstrated in clinical studies over a range of 1800 mg/day to 3600 mg/day. However, no additional benefit was demonstrated from the use of doses over 1800 mg/day.

Gabapentin available under the trade name Gralise (R):

Maintenance dose: Gralise (R) should be titrated to 1800 mg orally once daily with the evening meal.

Recommended titration schedule:
Day 1: 300 mg orally with the evening meal
Day 2: 600 mg orally with the evening meal
Days 3 through 6: 900 mg orally with the evening meal
Days 7 through 10: 1200 mg orally with the evening meal
Days 11 through 14: 1500 mg orally with the evening meal
Day 15: 1800 mg orally with the evening meal

Gralise (R) is not interchangeable with other gabapentin products because of differing pharmacokinetic profiles that affect the frequency of administration.

Gabapentin enacarbil extended release tablets available under the trade name Horizant (R):

The recommended dosage is 600 mg orally twice daily. Therapy should be initiated at a dose of 600 mg orally in the morning for 3 days of therapy, then increased to 600 mg twice daily (1,200 mg/day) on day four.

Gabapentin enacarbil extended release tablets available under the trade name Horizant (R) and gabapentin are not interchangeable.

Usual Adult Dose for Restless Legs Syndrome:

Gabapentin enacarbil available under the trade name Horizant (R):
600 mg orally once daily with food at about 5 PM

Usual Pediatric Dose for Epilepsy:

Less than 3 years: Effectiveness has not been established.

Greater than or equal to 3 and less than 12 years:
Starting Dose: ranges from 10 to 15 mg/kg/day in 3 divided doses.
Effective Dose: reached by upward titration over a period of approximately 3 days. The effective dose of gabapentin in patients 5 years of age and older is 25 to 35 mg/kg/day and given in divided doses (three times a day). The effective dose in pediatric patients ages 3 and 4 years is 40 mg/kg/day and given in divided doses (three times a day). Gabapentin may be administered as the oral solution, capsule, or tablet, or using combinations of these formulations. Dosages up to 50 mg/kg/day have been well tolerated in a long term clinical study. The maximum time interval between doses should not exceed 12 hours.

Greater than 12 years:

Initial dose: 300 mg orally on day one, 300 mg orally twice a day on day two, then 300 mg orally 3 times a day on day three.

Maintenance dose: 900 to 1800 mg orally in 3 divided doses. If necessary, the dose may be increased using 300 mg or 400 mg capsules three times a day up to 1800 mg/day.

Dosages up to 2400 mg/day have been well tolerated in long term clinical studies. Doses of 3600 mg/day have also been administered to a small number of patients for a relatively short duration, and have been well tolerated.

The maximum time between doses in the three times a day schedule should not exceed 12 hours.

Gabapentin Dosage Information

Gabapentin is highly lipophilic but not bound to plasma proteins, which show linear pharmacokinetics and do not show a link with any significant protein binding or liver metabolization. It has an oral bioavailability of greater than 90%, which is independent of dose. Generally, patients achieve steady-state plasma levels within 24 to 48 hours. There is no clinically significant effect in administration with food nor on the extent of absorption or elimination. The elimination half-life of the drug is approximately 6.5 hours. Gabapentin readily crosses the blood-brain barrier. It is primarily excreted through the renal path, with no active metabolites. Dosage adjustment is necessary for patients with renal impairment. Pregabalin does not induce or inhibit CYP enzymes. Also, none of the CYP enzyme inhibitors alter its pharmacokinetics as a consequence.

Initial treatment with gabapentin is usually started with one dose of 300 mg per day and later increases the frequency to 3 times a day and dosage up to 4800 mg per day. The recommendation is to start the first dose in the evening and then take the drug three times a day.
Usually, the effects are apparent in the first week of treatment but sometimes take about a month for significant improvement.
Taper the dose over more than seven days to discontinue the medication.

For Partial seizure

300 to 1200 mg 3 times per day by mouth
Max: 3600 mg per day

For Post-Herpetic Neuralgia

300 to 600 mg 3 times per day by mouth
Max: 1800 mg per day

For Neuropathic Pain

300 to 1200 mg 3 times per day by mouth
Max: 3600 mg per day

For Fibromyalgia

400 to 800 mg 3 times per day by mouth
Max: 2400 mg per day

Renal Dosing

Adjust the dose amount and frequency.

Creatinine clearance of 30 to 60: 200 to 700 mg twice per day
Creatinine clearance of 16 to 29: 200 to 700 mg once daily
Creatinine clearance of 15: 100 to 300 mg once daily
Creatinine clearance of less than 15: 125 to 350 mg as a supplement

How Should I Take Gabapentin?

Read the Gabapentin Medication Guide and, if available, the Patient Information Leaflet provided by your pharmacist before you start taking gabapentin and each time you get a refill. If you have any questions, ask your doctor or pharmacist.

Take this medication by mouth with or without food as directed by your doctor. Dosage is based on your medical condition and response to treatment. For children, the dosage is also based on weight.

If you are taking the tablets and your doctor directs you to split the tablet in half, take the other half-tablet at your next scheduled dose. Discard half tablets if not used within several days of splitting them. If you are taking the capsules, swallow them whole with plenty of water.

It is very important to follow your doctor’s dosing instructions exactly. During the first few days of treatment, your doctor may gradually increase your dose so your body can adjust to the medication. To minimize side effects, take the very first dose atbedtime.

Take this medication regularly to get the most benefit from it. This drug works best when the amount of medicine in your body is kept at a constant level. Therefore, take gabapentin at evenly spaced intervals at the same time(s) each day. If you are taking this medication 3 times a day to control seizures, do not let more than 12 hours pass between doses because your seizures may increase.

Do not take this medication more often or increase your dose without consulting your doctor. Your condition will not improve any faster and the risk of serious side effects may increase.

Do not stop taking this medication without consulting your doctor. Some conditions may become worse when the drug is suddenly stopped. Your dose may need to be gradually decreased.

Antacids containing aluminum or magnesium may interfere with the absorption of this medication. Therefore, if you are also taking an antacid, it is best to take gabapentin at least 2 hours after taking the antacid.

Different forms of gabapentin (such as immediate-release, sustained-release, enacarbil sustained-release) are absorbed in the body differently. Do not switch from one form to the other without consulting your doctor.

Tell your doctor if your condition does not improve or if it worsens.

The Horizant brand of gabapentin should not be taken during the day. For best results, take Horizant with food at about 5:00 in the evening.

Both Gralise and Horizant should be taken with food.

Neurontin can be taken with or without food.

If you break a Neurontin tablet and take only half of it, take the other half at your next dose. Any tablet that has been broken should be used as soon as possible or within a few days.

Measure liquid medicine with the dosing syringe provided, or with a special dose-measuring spoon or medicine cup. If you do not have a dose-measuring device, ask your pharmacist for one.

If your doctor changes your brand, strength, or type of gabapentin, your dosage needs may change.Ask your pharmacist if you have any questions about the new kind of gabapentin you receive at the pharmacy.

Do not stop using gabapentin suddenly, even if you feel fine. Stopping suddenly may cause increased seizures. Follow your doctor’s instructions about tapering your dose.

Wear a medical alert tag or carry an ID card stating that you take gabapentin. Any medical care provider who treats you should know that you take seizure medication.

Gabapentin can cause you to have a false positive urine protein screening test. If you provide a urine sample for testing, tell the laboratory staff that you are taking gabapentin.

Store tablets and capsules at room temperature away from light and moisture.

Store the liquid medicine in the refrigerator. Do not freeze.

Gabapentin Dosage for Children

Gabapentin is used to help control partial seizures (convulsions) in the treatment of epilepsy. This medicine cannot cure epilepsy and will only work to control seizures for as long as you continue to take it.

Gabapentin is also used to manage a condition called postherpetic neuralgia, which is pain that occurs after shingles.

Gabapentin works in the brain to prevent seizures and relieve pain for certain conditions in the nervous system. It is not used for routine pain caused by minor injuries or arthritis. Gabapentin is an anticonvulsant.

This medicine is available only with your doctor’s prescription.

This product is available in the following dosage forms:

- - Capsule
  - Tablet
  - Tablet, Extended Release, 24 HR
  - Solution
  - Suspension

Gabapentin Dosage for Children

Please remember that you are not allowed to buy Gabapentin Online if you are 19 years old and under. Please find a local doctor to prescribe you Gabapentin prescription and buy it in a local Gabapentin pharmacy.

Gabapentin is FDA-approved as a secondary treatment for partial seizures in children 3 years or older with epilepsy. The use of gabapentin in children for any other medical condition is not FDA-approved. Dosing will be determined by both the child’s age and weight.

Gabapentin dosage by age for children older than 3 years
Age (yr)	Recommended dosage
3-4 yrs	40 mg per kg (18.2 mg/lb) of body weight divided into three doses Maximum: 50 mg per kg (22.7 mg/lb) of body weight daily
5-11 yrs	20-35 mg per kg (9.1-15.9 mg/lb) of body weight divided into three doses Maximum: 50 mg per kg (22.7 mg/lb) of body weight daily
12 yrs or older	300-600 mg taken three times per day Maximum: 3600 mg per day