Neuropathic pain is a chronic nerve pain that can significantly impair a patient’s functioning and quality of life. Neuropathic pain results from damaged nerves that have been affected by tissue injury due to trauma or disease. Diabetes mellitus and herpes zoster are commonly associated with the development of neuropathies. Other disease states that may result in neuropathic pain include complex regional pain syndrome, radiculopathy, and phantom limb pain.
Neuropathic pain can also be medicationrelated, as in the case of nerve damage due to cancer treatment.
Neuropathic pain originates from the reduced inability of a neuron to relay messages to and from the brain because of damage to the nerve. This can cause a person to feel a variety of sensations or hypersensitivities.1,2 A patient may feel different types of pain, depending on the origin and cause of the pain.
Neuropathic pain can be distinguished from nociceptive pain by determining the quality of the pain. Typically, patients experience variations in sensation or hypersensitivity. Neuropathic pain symptoms can be classified as negative or positive. Negative symptoms of neuropathic pain are described as a loss of sensation or numbness. Positive symptoms are characterized by the increased perception of pain or abnormal sensations. Positive symptoms can be either induced by a stimulus or spontaneous (nonstimulus induced).
Gabapentin at doses of 1800 mg to 3600 mg daily (1200 mg to 3600 mg gabapentin encarbil) can provide good levels of pain relief to some people with postherpetic neuralgia and peripheral diabetic neuropathy. Evidence for other types of neuropathic pain is very limited.
The outcome of at least 50% pain intensity reduction is regarded as a useful outcome of treatment by patients, and the achievement of this degree of pain relief is associated with important beneficial effects on sleep interference, fatigue, and depression, as well as quality of life, function, and work.
Around 3 or 4 out of 10 participants achieved this degree of pain relief with gabapentin, compared with 1 or 2 out of 10 for placebo. Over half of those treated with gabapentin will not have worthwhile pain relief but may experience adverse events. Conclusions have not changed since the previous update of this review.
Gabapentin is a medication sometimes prescribed to people who have epileptic seizures. This drug also can be used to treat chronic pain, specifically neuropathic pain. Neuropathic pain is often described as a very sharp, shooting type of pain that stems from a problem with the central nervous system.
Using gabapentin for pain is just one of many options available to chronic pain patients. A person’s success level when it comes to using gabapentin for pain relief can depend on the type of medical condition causing the pain and other treatments he or she is undergoing.
Patients suffering from conditions such as diabetes, multiple sclerosis, fibromyalgia and shingles may have success with taking gabapentin for pain treatment. Some people may be prescribed gabapentin as their sole form of pain treatment, while others may take this medication in conjunction with narcotic pain relievers.
Gabapentin typically is given to those suffering from a life-long illness involving pain and is not an optimal pain treatment for short-term problems such as a broken bone.
This medication needs time to build up in the body and is not an overnight pain solution. A patient should not stop taking gabapentin abruptly just because he or she is not experiencing immediate positive results. A person who is concerned about whether gabapentin is helping his or her pain should consult a doctor.
If a patient who quits taking gabapentin does not do so properly, then he or she may experience withdrawal symptoms such as chest pain, insomnia and extreme anxiety.
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
Is Gabapentin Addictive ?
No. Gabapentin is not considered addictive.
But it is possible to develop a physical dependence on the drug. In fact, people can experience withdrawal symptoms for up to 45 days after they stop taking gabapentin. Although gabapentin does give some people a euphoric “high” which can cause gabapentin abuse, gabapentin abusers do not present with the kind of compulsive, drug-seeking behavior or strong cravings that indicates addiction.
Unfortunately, our clinical experience suggests that gabapentin is now prevalent as a drug of abuse. The drug’s effects vary with the user, dosage, past experience, psychiatric history, and expectations. Individuals describe varying experiences with gabapentin abuse, including: euphoria, improved sociability, a marijuana-like ‘high’, relaxation, and sense of calm, although not all reports are positive (for example, ‘zombie-like’ effects).
In primary care, an increasing number and urgency of prescription requests cannot necessarily be explained by the increased number of cases of neuropathic pain. In the substance misuse service, the numbers admitting to using gabapentin are also growing.
A 2007 report described the case of a 67-year-old woman with mood disorders and a history of alcohol abuse who was prescribed gabapentin (as well as naproxen and amitriptyline) for pain from polyneuritis. Owing to tolerance, she was prescribed 4800 mg/day (over the maximum recommended dose), but further escalated her intake to 7200 mg daily. She requested gabapentin without a prescription from pharmacists and visited numerous physicians, exaggerating her symptoms, to obtain the desired quantities.
When the patient was finally no longer able to obtain gabapentin through these methods, she developed withdrawal symptoms, characterized by trembling, sweating, excitation, pallor, and exophthalmia. The withdrawal required hospitalization, where a change to alternative pain control medications was made. Within several months, the patient had resumed abuse of gabapentin.
Another report described 3 cases of gabapentin-associated withdrawal symptoms after abrupt discontinuation of total daily doses of 4800 mg, 3600 mg, and 2400 mg.
Similar symptoms were reported in 2 patients with histories of alcohol abuse. The first case involved a 33-year-old man taking 3600 mg of gabapentin daily, which was twice his prescribed dose. He had been obtaining gabapentin refills early to reduce his craving for alcohol and make him feel calmer. When further refills were denied, he abruptly stopped taking the gabapentin and suffered acute withdrawal symptoms.
The second case described a 63-year-old man with a history of alcohol abuse who was taking gabapentin at 4900 mg/day instead of the prescribed 1800 mg/day. After presentation to the hospital and discontinuation of gabapentin, he developed severe withdrawal symptoms. Withdrawal symptoms in these patients included disorientation, confusion, tachycardia, diaphoresis, tremulousness, and agitation. The withdrawal symptoms resolved upon resumption of gabapentin.
The use of nonprescribed gabapentin by patients attending substance abuse clinics has also been reported.
A questionnaire-based survey completed by 129 respondents attending 6 substance abuse treatment clinics found that 22% of patients admitted to using nonprescribed gabapentin. As a comparison, nonprescribed use of pregabalin was 3%, benzodiazepines 47%, and cannabis 43%.
Some patients taking nonprescribed gabapentin reported using the drug to become intoxicated or to potentiate the effect of methadone.
Gabapentin is an anti-epileptic drug, also called an anticonvulsant. It affects chemicals and nerves in the body that are involved in the cause of seizures and some types of pain.
Gabapentin is used together with other medicines to treat partial seizures in adults and children at least 3 years old.
Gabapentin is also used to treat neuropathic pain (nerve pain) caused by herpes virus or shingles (herpes zoster) in adults.
Use only the brand and form of gabapentin your doctor has prescribed. Check your medicine each time you get a refill to make sure you receive the correct form.
The Gralise brand of gabapentin is indicated for the management of neuropathic pain only. It is not used for epilepsy.
Horizant is used to treat nerve pain and restless legs syndrome (RLS).
The Neurontin brand is used to treat seizures in adults and children who are at least 3 years old, in addition to neuropathic pain.
What is Gabapentin side effects ?
Gabapentin may cause side effects. Tell your doctor if any of these symptoms are severe or do not go away:
drowsiness
tiredness or weakness
dizziness
headache
uncontrollable shaking of a part of your body
double or blurred vision
unsteadiness
anxiety
memory problems
strange or unusual thoughts
unwanted eye movements
nausea
vomiting
heartburn
diarrhea
dry mouth
constipation
increased appetite
weight gain
swelling of the hands, feet, ankles, or lower legs
back or joint pain
fever
runny nose, sneezing, cough, sore throat, or flu-like symptoms
ear pain
red, itchy eyes (sometimes with swelling or discharge)
Some side effects may be serious. If you experience any of the following symptoms, call your doctor immediately:
rash
itching
swelling of the face, throat, tongue, lips, or eyes
hoarseness
difficulty swallowing or breathing
seizures
Gabapentin may cause other side effects. Call your doctor if you have any unusual problems while taking this medication.
Call your doctor at once if you have:
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;
rapid back and forth movement of your eyes; or
severe skin reaction — fever, sore throat, swelling in your face or tongue, burning in your eyes, skin pain, followed by a red or purple skin rash that spreads (especially in the face or upper body) and causes blistering and peeling.
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.
Common gabapentin side effects may include:
dizziness, drowsiness;
dry mouth, blurred vision;
headache;
diarrhea; or
swelling in your hands or feet.
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.
Gabapentin 300mg
Can You Overdose On Gabapentin?
Compared with some drugs, such as opioids, gabapentin appears to be relatively non-lethal in overdose situations, meaning the morbidity associated with a toxic dose is low. However, the primary danger of gabapentin overdose appears when individuals use gabapentin in conjunction with other drugs, such as alcohol or opioids.
Mixing substances with central nervous system depressant effects can easily result in an amplification of certain side effects and can lead to significant issues, including overdose. For instance, individuals using gabapentin in conjunction with alcohol are subject to intensified depressant side effects such as sedation and dizziness. Alcohol itself may also cause a more rapid release of the contents of certain extended-release tablet formulations of the drug, potentially putting the user at greater risk of gabapentin overdose.
Alcohol isn’t the only danger for those using gabapentin. Among those on a prescription opioid regimen, being concurrently prescribed gabapentin is associated with a substantially increased risk of opioid-related death.
an overdose of gabapentin may result in the following symptoms:
Dizziness.
Drowsiness.
Double vision.
Slurred speech
Diarrhea.
Nausea.
Vomiting.
Loss of control of bodily movements (ataxia).
Low blood pressure.
Rapid heart rate.
Labored breathing.
Coma (in patients with kidney failure).
Gabapentin overdoses are often medically managed without significant complications. Nonetheless, any type of drug overdose can be very serious, and some individuals may experience more severe reactions in the setting of a gabapentin overdose. For instance, children, elderly individuals, and those with impaired renal function may be at a much higher risk of complications from a toxic dose of gabapentin than healthy adults.
The concurrent ingestion of other substances may also result in a more dire medical situation and, as mentioned, could increase the likelihood of overdose death. Individuals who overdose on a combination of gabapentin and another drug with depressant effects (e.g., alcohol, benzodiazepines, opioids, etc.) are at serious risk of significant adverse effects, and these individuals may require immediate medical attention.
Gabapentin may cause respiratory depression when used alone or with other substances. Combining the drug with other respiratory depressing substances may be deadly.
Unfortunately, it is all too common for gabapentin to be prescribed to individuals who also use opioids, the combination of which can result in profound respiratory depression (especially when these drugs are misused in larger-than-recommended doses).
Because of the very real risk of dangerously slowed breathing and, ultimately, respiratory arrest, those who abuse gabapentin to intensify an opioid high may risk death with each use.
Depending on the severity of any resultant oxygen deprivation and the length of time that it persists, consequences may include:
The total number of patients treated with Neurontin in controlled clinical trials in patients with postherpetic neuralgia was 336, of which 102 (30%) were 65 to 74 years of age, and 168 (50%) were 75 years of age and older. Totally 80% Gabapentin patients are seniors.
There was a larger treatment effect in patients 75 years of age and older compared with younger patients who received the same dosage.
Gabapentin
Since gabapentin is almost exclusively eliminated by renal excretion, the larger treatment effect observed in patients ≥ 75 years may be a consequence of increased gabapentin exposure for a given dose that results from an age-related decrease in renal function. However, other factors cannot be excluded. The types and incidence of adverse events were similar across age groups except for peripheral edema and ataxia, which tended to increase in incidence with age.
Clinical studies of Neurontin in epilepsy did not include sufficient numbers of subjects aged 65 and over to determine whether they responded differently from younger subjects. Other reported clinical experience has not identified differences in responses between the elderly and younger patients.
In general, dose selection for an elderly patient should be cautious, usually starting at the low end of the dosing range, reflecting the greater frequency of decreased hepatic, renal, or cardiac function, and of concomitant disease or other drug therapy.
This drug is known to be substantially excreted by the kidney, and the risk of toxic reactions to this drug may be greater in patients with impaired renal function. Because elderly patients are more likely to have decreased renal function, care should be taken in dose selection, and dose should be adjusted based on creatinine clearance values in these patients
Pediatrics: The safety and efficacy in patients under the age of 18 have not been established.
Safety data in 39 patients between the ages of 12 and 18 years included in the double-blind, placebo-controlled trials showed that, at doses of 900 to 1200 mg/day, the incidence of adverse events in this group of patients was similar to that observed in older individuals.
In controlled clinical trials involving patients, 3 to 12 years of age (N=323), psychiatric adverse events such as emotional lability, hostility, hyperkinesia and thought disorder were reported at a higher frequency in patients treated with gabapentin compared to placebo. Geriatrics: Systematic studies in geriatric patients have not been conducted. Adverse clinical events reported among 59 patients over the age of 65 years treated with Neurontin did not differ from those reported for younger individuals. The small number of individuals evaluated and the limited duration of exposure limits the strength of any conclusions reached about the influence of age, if any, on the kind and incidence of adverse events associated with the use of Neurontin.
Gapapentin for Neuropathic Pain
Gabapentin (Neurontin) has FDA indication to treat postherpetic neuralgia and partial onset seizures. Controlled clinical trials in diabetic neuropathy and postherpetic neuralgia show that gabapentin at 2400-3600 mg/day has a similar efficacy to tricyclic antidepressants and carbamazepine. Consistent, though less compelling clinical evidence supports its use for neuropathic cancer pain, pain associated with HIV infection, chronic back pain and others (readers wanting more in depth research findings are urged to consult Reference 1). Due to this emerging evidence, it is widely used for the treatment of neuropathic pain. The exact mechanism and site of action of gabapentin is unknown. Gabapentin is generally well-tolerated, easily titrated, has few drug interactions, and does not require laboratory monitoring. However, cost may be a limiting factor for some patients. Patients suitable for gabapentin should have a clear neuropathic pain syndrome, characterized by sharp, shooting, lancinating and/or burning pain, in a nerve root (radicular) or stocking/glove distribution. See Fast Fact #289 for a comparison of gabapentin with pregabalin a similar neuropathic analgesic. Adult Dosing Gabapentin is started at low doses (100 mg to 300 mg total daily) and increased by 100 – 300 mg every 1-3 days to effect. A typical schedule might be: day 1-2: 300 mg nightly; day 3-4: 300 mg twice daily; day 5-7: 600 mg twice daily; day 8 onwards: 600 mg three times a day. The usual effective total daily dose is 900-3600 mg, administered in three divided doses per day. Titration should proceed more slowly in elderly patients. If gabapentin is discontinued, it should be done over a minimum of a week to prevent withdrawal seizures. Pediatric Use There is limited data available assessing its effectiveness in neuropathic pain in children. The American Pain Society recommends that gabapentin be considered for pediatric neuropathic pain especially when concurrent analgesics are found to be too sedating. Their recommended initial dose is 2 mg/kg/day with a usual dosage range of 8 to 35 mg/kg/day divided into 3 daily doses. Dosing in Renal Failure Gabapentin doses must be reduced for patients with renal insufficiency.
Creatinine Clearance (CrCl) 30-60 ml/min: maximum daily dose is 1400 mg, divided.
CrCl 16-30 ml/min: maximum daily dose is 700 mg, given once daily.
CrCl 15ml/min: maximum daily dose is 300 mg, once daily. Doses should decrease proportionally for CrCl less than 15 ml/min (e.g. 300 mg every other day for a CrCl of ~7.5 ml/min).
For patients on hemodialysis a supplemental dose is usually given after dialysis (usually 100-300 mg).
Adverse Reactions Sedation, confusion, dizziness, and ataxia are the most common side effects, especially with rapid dose titration. Tolerance to these effects appears to develop within a few days if the dose is held at the highest tolerated dose until symptoms improve or stabilize. Dosage Formulations Gabapentin is available in 100 mg, 300 mg, and 400 mg capsules, 600 mg and 800 mg tablets, and as a liquid (250mg/5mL). Cost Gabapentin is more expensive than older agents used for neuropathic pain (tricyclic antidepressants and older anti-epileptic drugs such as carbamazepine). Generic gabapentin is available, although can cost ~$100 for 90 600 mg tablets. Other Palliative Care Uses of Gabapentin Small scale published trials have shown efficacy in the treatment of severe chronic hiccups, pruritus, postoperative pain and delirium, restless leg syndrome and hot flashes. Perhaps more compelling is its potential efficacy for chronic cough for which a randomized double-blind placebo controlled trial demonstrated significant improvement in cough-specific quality of life, cough frequency, and cough severity. See Fast Fact #200. Summary Gabapentin is a safe and effective adjuvant analgesic for neuropathic pain. Physicians should become comfortable using and titrating gabapentin in patients with neuropathic pain syndromes.
References
Moore R, Wiffen PJ, Derry S, Toelle T, Rice AS C. Gabapentin for chronic neuropathic pain and fibromyalgia in adults. Cochrane Database of Systematic Reviews 2014, Issue 4. Art. No.: CD007938. DOI: 10.1002/14651858.CD007938.pub3
Mishra S, Bhatnagar S, et al. A comparative efficacy of amitriptyline, gabapentin, and pregabalin in neuropathic cancer pain: a prospective randomized double-blind placebo-controlled study. American Journal of Hospice and Palliative Medicine 2012;29:177-182.
Caraceni A, et al. Gabapentin for neuropathic cancer pain: a randomized controlled trial from the gabapentin cancer pain study group. J Clin Onc. 2004; 22:2909-2917.
American Pain Society. Principles of Analgesic Use in the Treatment of Acute Pain and Cancer Pain. 6th ed, Glenview, IL: American Pain Society, 2008.
Micromedex Drug Database. Thompson Reuters. http://www.micromedex.com.
Giampiero P, Aielli F, et al. Gabapentin in the treatment of hiccups in patients with advanced cancer: a 5-year experience. Clin Neuropharm 2010; 33:179-180.
Anand S, Gabapentin for pruritus in palliative care. Am J of Hospice and Pall Med 2012; 30:192-196.
Dauri M, Faria S, Gatti A, et al. Gabapentin and Pregabalin for the Acute Post-operative Pain Management. A Systematic-Narrative Review of the Recent Clinical Evidences. Curr Drug Targets 2009, 10(8):716-33.
Leung JM, Sands LP, et al. Pilot clinical trial of gabapentin to decrease postoperative delirium in older patients. Neurology. 2006; 67:310-314.
Saletu M, Anderer P, Saletu-Zyhlarz GM, et al. Comparative Placebo-Controlled Polysomnographic and Psychometric Studies on the Acute Effects of Gabapentin Versus Ropinirole in Restless Legs Syndrome. J Neural Transm 2010, 117(4):463-73.
Butt DA, Lock M, Lewis JE, et al. Gabapentin for the Treatment of Menopausal Hot Flashes: A Randomized Controlled Trial. Menopause 2008; 15(2):310-8.
Version History: This Fast Fact was originally edited by David E Weissman MD. 2nd Edition published August 2005; 3rd Edition May 2015. Version re-copy-edited April 2009; then again May 2015; renal dosing information adjusted to reflect current recommendations, and updated cost information added.
Fast Facts and Concepts are edited by Sean Marks MD (Medical College of Wisconsin) and associate editor Drew A Rosielle MD (University of Minnesota Medical School), with the generous support of a volunteer peer-review editorial board, and are made available online by the Palliative Care Network of Wisconsin (PCNOW); the authors of each individual Fast Fact are solely responsible for that Fast Fact’s content. The full set of Fast Facts are available at Palliative Care Network of Wisconsin with contact information, and how to reference Fast Facts.
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There are many drugs used to treat anxiety. New studies are now showing that Gabapentin has been a successful treatment for individuals who suffer from anxiety. However, there are no randomized controlled trials on the effectiveness of this medication in generalized anxiety disorder (GAD), and there are only a few case reports.
People with GAD who take Gabapentin have shown to be less irritable, reduce the use of alcohol as self-medication, have fewer depression symptoms, feel less anxious anticipating the future, improve in phobic avoidance (going out in public more and experiencing a significant decrease in panic disorder and reduction of panic attacks).
Gabapentin is an anticonvulsant drug that is primarily used to treat seizures and the pain that follows after an episode of shingles. Gabapentin is considered an off-brand drug used to treat anxiety. Neurontin is the most common brand name for Gabapentin, as well as Horizant and Gralise. Gabapentin has shown to help people with sleeping better, as insomnia is a symptom of anxiety.
Side Effects of Gabapentin
Like all medications, there are several side effects to taking Gabapentin. Side effects that you experience are relative to your personal reaction to the drug. Everyone is different, so you may not experience side effects that others do or don’t. Some side effects can be nausea, vomiting, tremors, dizziness, sleepiness, double vision, loss of control of bodily movements, fluid retention, difficulty speaking, jerky movements, unusual eye movements, double vision, and unsteadiness.
If you begin to experience any of these symptoms, speak with your doctor immediately. Get emergency help if you suspect you are having an allergic reaction like; swelling of your face, lips, tongue, or throat, hives, and difficulty breathing. If you notice that your symptoms are worsening, contact your doctor immediately. You may not notice symptoms until weeks after taking Gabapentin.
Is Gabapentin Approved by the U.S. Food and Drug Administration (FDA) ?
Gabapentin was originally approved by the U.S. Food and Drug Administration (FDA) in December 1993, for use as an adjuvant medication to control partial seizures (effective when added to other antiseizure drugs) in adults; that indication was extended to children in 2000. In 2004, its use for treating postherpetic neuralgia (neuropathic pain following shingles) was approved.
Gabapentin is best known under the brand name Neurontin manufactured by Pfizer subsidiary Parke-Davis. A Pfizer subsidiary named Greenstone markets generic gabapentin.
In December 2004 the FDA granted final approval to a generic equivalent to Neurontin made by the Israeli firm Teva.
Neurontin began as one of Pfizer’s best selling drugs; however, Pfizer has come under heavy criticism and serious litigation for its marketing of the drug.
They face allegations that, behind the scenes, Parke-Davis marketed the drug for at least a dozen supposed uses that the FDA had not approved.
Today it is a mainstay drug for migraines, even though it was not approved for such use in 2004.
What is Gabapentin Used for ?
Gabapentin comes as a capsule, a tablet, an extended-release (long-acting) tablet, and an oral solution (liquid) to take by mouth. Gabapentin capsules, tablets, and oral solution are usually taken with a full glass of water (8 ounces [240 milliliters]), with or without food, three times a day.
These medications should be taken at evenly spaced times throughout the day and night; no more than 12 hours should pass between doses. The extended-release tablet (Horizant) is taken with food once daily at about 5 PM. Follow the directions on your prescription label carefully, and ask your doctor or pharmacist to explain any part you do not understand. Take gabapentin exactly as directed. Do not take more or less of it or take it more often than prescribed by your doctor.
Gabapentin extended-release tablets cannot be substituted for another type of gabapentin product. Be sure that you receive only the type of gabapentin that was prescribed by your doctor. Ask your pharmacist if you have any questions about the type of gabapentin you were given.
Swallow the extended-release tablets whole; do not cut, chew, or crush them.
If your doctor tells you to take one-half of a regular tablet as part of your dose, carefully split the tablet along the score mark. Use the other half-tablet as part of your next dose. Properly dispose of any half-tablets that you have not used within several days of breaking them.
If you are taking gabapentin to control seizures or PHN, your doctor will probably start you on a low dose of gabapentin and gradually increase your dose as needed to treat your condition. If you are taking gabapentin to treat PHN, tell your doctor if your symptoms do not improve during your treatment.
Gabapentin may help to control your condition but will not cure it. Continue to take gabapentin even if you feel well. Do not stop taking gabapentin without talking to your doctor, even if you experience side effects such as unusual changes in behavior or mood. If you suddenly stop taking gabapentin tablets, capsules, or oral solution, you may experience withdrawal symptoms such as anxiety, difficulty falling asleep or staying asleep, nausea, pain, and sweating. If you are taking gabapentin to treat seizures and you suddenly stop taking the medication, you may experience seizures more often. Your doctor may decrease your dose gradually over at least a week.
Your doctor or pharmacist will give you the manufacturer’s patient information sheet (Medication Guide) when you begin treatment with gabapentin and each time you refill your prescription. Read the information carefully and ask your doctor or pharmacist if you have any questions. You can also visit the Food and Drug Administration (FDA) website (http://www.fda.gov/Drugs) or the manufacturer’s website to obtain the Medication Guide.
Off-label use exposes patients to adverse effects and generally is not supported by evidence.
The only conditions for which gabapentinoid drugs are FDA-approved to manage pain are postherpetic neuralgia (both gabapentin and pregabalin [Lyrica]) and diabetic neuropathy, spinal cord injury, and fibromyalgia (pregabalin only). Nevertheless, use of these drugs has tripled during the past 15 years. This increase likely reflects gabapentinoid use for managing non–FDA-approved pain conditions, in part to avoid opioid use. In this review, researchers identified 34 placebo-controlled randomized trials (with ≈4200 patients) of gabapentinoids for noncancer, non–FDA-approved pain conditions. Most trials’ durations were 4 to 12 weeks.
Results of the review were as follows:
Only weak evidence supports use of gabapentin for diabetic neuropathy (only pregabalin is approved for this indication).
Minimal evidence supports use of gabapentin for nondiabetic painful neuropathies.
Studies of gabapentinoids for managing low back pain or sciatica have been largely negative.
Only minimal evidence supports a clinically meaningful benefit of off-label gabapentin use for fibromyalgia (for which pregabalin is approved).
Both gabapentin and pregabalin are approved for managing postherpetic neuralgia, but both are used often for acute zoster pain, for which studies have shown no benefit.
A small number of studies of gabapentinoid use for other pain syndromes (e.g., traumatic nerve injury, complex regional pain syndrome, burn injury, sickle cell pain) showed no clinically important benefits.
COMMENT
The markedly increased off-label use of gabapentinoids to manage pain has no or limited evidence of benefit. This practice is worrisome, especially given known high rates of side effects, including dizziness, somnolence, and unsteadiness. In addition, the authors note that patients often are prescribed gabapentinoids to avoid opioid use, but such patients sometimes still use opioids, either prescribed or illicit. The combination of gabapentinoids and opioids is associated with excess risk for opioid overdose.
Dr. Brett is an author of this article and is the Editor-in-Chief of NEJM Journal Watch General Medicine; however, he had no role in selecting or summarizing this article.
How to use gabapentin oral ?
Read the 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 at bedtime.
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.
COMMENT
The markedly increased off-label use of gabapentinoids to manage pain has no or limited evidence of benefit. This practice is worrisome, especially given known high rates of side effects, including dizziness, somnolence, and unsteadiness. In addition, the authors note that patients often are prescribed gabapentinoids to avoid opioid use, but such patients sometimes still use opioids, either prescribed or illicit. The combination of gabapentinoids and opioids is associated with excess risk for opioid overdose.