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
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 Gabapentin is Used
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.
Gabapentin may be used as part of a combination therapy. This means you may need to take it with other drugs.
Gabapentin Dosage for Adults
For adults, the gabapentin dosage can vary widely depending on the condition being treated. Upon starting treatment with gabapentin, the starting dose may be 100 to 300 mg per day and steadily increase until an effective dose is reached. The maximum dosage will depend on the condition being treated.
Standard gabapentin dosage for adults: 300-600 mg taken three times per day.
Maximum gabapentin dosage for adults: 1200 mg taken three times per day for a maximum daily dose of 3600 mg.
Gabapentin Dosage Chart for Adult
Indication
Age
Standard dosage
Maximum dosage
Partial seizures
12 years and older
300-600 mg three times per day
3600 mg per day
5-11 years
25-35 mg/kg (11.4-15.9 mg/lb) per day divided into three daily doses
50 mg/kg (22.7 mg/lb) per day
3-4 years
40 mg/kg (18.2 mg/lb) per day divided into three daily doses
50 mg/kg (22.7 mg/lb) per day
Postherpetic neuralgia
18 years and older
300 mg on day 1, 300 mg twice daily on day 2, then 300 mg three times daily on day 3; dosage may be further increased after day 3 to 600 mg three times per day
1800 mg per day
Diabetic peripheral neuropathy
18 years and older
300-1200 mg three times per day (off-label)
3600 mg per day
Fibromyalgia
18 years and older
600 mg twice daily and 1200 mg at bedtime (off-label)
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.4 During 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.
Gabapentin Dosage
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
Gabapentin 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 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.
Gabapentin dosage forms and strengths
Gabapentin is taken by mouth as a tablet, capsule, or oral solution.
Tablets: 600 or 800 mg per tablet
Capsules: 100, 300, or 400 mg per capsule
Liquid: 250 mg per 5 milliliters (ml) oral liquid
Gabapentin dosage for adults
For adults, the gabapentin dosage can vary widely depending on the condition being treated. Upon starting treatment with gabapentin, the starting dose may be 100 to 300 mg per day and steadily increase until an effective dose is reached. The maximum dosage will depend on the condition being treated.
Standard gabapentin dosage for adults: 300-600 mg taken three times per day.
Maximum gabapentin dosage for adults: 1200 mg taken three times per day for a maximum daily dose of 3600 mg.
Gabapentin dosage for children
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.
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 dosesMaximum: 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 dosesMaximum: 50 mg per kg (22.7 mg/lb) of body weight daily
12 yrs or older
300-600 mg taken three times per dayMaximum: 3600 mg per day
Gabapentin dosage chart
Indication
Age
Standard dosage
Maximum dosage
Partial seizures
12 years and older
300-600 mg three times per day
3600 mg per day
5-11 years
25-35 mg/kg (11.4-15.9 mg/lb) per day divided into three daily doses
50 mg/kg (22.7 mg/lb) per day
3-4 years
40 mg/kg (18.2 mg/lb) per day divided into three daily doses
50 mg/kg (22.7 mg/lb) per day
Postherpetic neuralgia
18 years and older
300 mg on day 1, 300 mg twice daily on day 2, then 300 mg three times daily on day 3; dosage may be further increased after day 3 to 600 mg three times per day
1800 mg per day
Diabetic peripheral neuropathy
18 years and older
300-1200 mg three times per day (off-label)
3600 mg per day
Fibromyalgia
18 years and older
600 mg twice daily and 1200 mg at bedtime (off-label)
2400 mg per day
Alcohol dependence
18 years and older
300-600 mg three times per day (off-label)
1800 mg per day
Gabapentin dosage for partial seizures
Gabapentin is FDA approved as adjunctive therapy for partial seizures in adults and children 3 years of age or older.
Standard gabapentin dosage for adults: 300 to 600 mg taken three times per day by mouth.
Maximum gabapentin dosage for adults: 3600 mg daily in three divided doses.
Renally impaired patients (kidney disease)—dose amount and dose frequency adjustment:
Creatinine clearance of 30-59 ml/min: 200 to 700 mg twice per day
Creatinine clearance of 16-29 ml/min: 200 to 700 mg once per day
Creatinine clearance of 15 ml/min or less: 100 to 300 mg once per day decreased proportionately (1/15 per whole number value) for each decrease in creatinine clearance
Hemodialysis: dose is dependent on estimated creatinine clearance; a supplemental dose of 125 to 350 mg is given after dialysis
Gabapentin dosage for nerve pain due to shingles (postherpetic neuralgia)
Gabapentin is FDA approved to treat postherpetic neuralgia, that is, neuropathic pain due to shingles (herpes zoster).
Standard gabapentin dosage for adults: 300 to 600 mg taken three times per day by mouth.
Maximum gabapentin dosage for adults: 1800 mg daily in three divided doses.
Renally impaired patients (kidney disease): See dosage for renal impaired patients above
Gabapentin dosage for neuropathic pain
Gabapentin is most frequently prescribed off-label to treat nerve pain (neuralgia) due to nerve damage (neuropathy), compression, or irritation.
Standard gabapentin dosage for adults: 300 to 1200 mg taken three times per day by mouth.
Maximum gabapentin dosage for adults: 3600 mg daily in three divided doses.
Renally impaired patients (kidney disease): See dosage for renal impaired patients above
Gabapentin dosage for fibromyalgia
Gabapentin is used off-label to reduce fatigue, provide pain relief, and improve sleep in patients with fibromyalgia.
Standard gabapentin dosage for adults: 600 mg twice daily and 1200 mg at bedtime.
Maximum gabapentin dosage for adults: 2400 mg daily.
Renally impaired patients (kidney disease): See dosage for renal impaired patients above
Gabapentin dosage for alcohol dependence
Gabapentin is widely used off-label to reduce insomnia and cravings in people with alcohol use disorder, particularly those in the maintenance phase of alcohol abstinence.
Standard gabapentin dosage for adults: 300 to 600 mg taken three times per day by mouth.
Maximum gabapentin dosage for adults: 1800 mg daily in three divided doses.
Renally impaired patients (kidney disease): See dosage for renal impaired patients above
Gabapentin dosage for pets
You should not give gabapentin to animals unless a veterinarian has given the animal a prescription for gabapentin. Veterinarians frequently prescribe gabapentin to treat seizures or chronic nerve pain in pets and large animals. The recommended dose is 5-10 mg per kilogram of body weight (2.3-4.5 mg/lb) every 12 hours, but dosing will vary between veterinarians. Gabapentin dosages can vary from 3 to 11 mg per kilogram (1.4 to 5 mg per pound) as an analgesic to 10 to 30 mg mg per kilogram (4.5 to 13.6 per pound) as an anticonvulsant. As with people, the dose may start small and steadily increase until an effective dose is reached.
First, we must consider the different neuropathic pain types. Neuropathic pain can be diverse in nature, encompassing a wide range of pain types, including post-herpetic neuralgia (PHN), painful diabetic peripheral neuropathy (DPN), and painful cancer-related neuropathies.
Gabapentin has been shown to be beneficial in treating several types of neuropathic pain; however, the mechanism of action by which gabapentin exerts its analgesic effect is still unknown.
It is suggested that gabapentin may block the calcium channel alpha(2)delta (a2d)-1 receptor in the brain. This protein-modulated receptor is involved in excitatory synapse formation. Therefore, the therapeutic effects of gabapentin may be attributed to prevention of new synapse formations.
Gabapentin was shown to offer substantial improvement in neuropathic pain with side effects that were similar to those on placebo.
Even with sufficient data supporting the use of gabapentin in the treatment of various neuropathic pain conditions, gabapentin only has Food and Drug Administration (FDA) approval for PHN. Dosing recommendations for off-label use of gabapentin can be somewhat ambiguous, if a recommendation exists at all. Therefore, several studies further investigate dosing regimens specific to other neuropathic pain syndromes.
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.
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.During 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.
ADEs and withdrawal rates for patients taking gabapentin doses of 1,200 mg/d or greater were compared to those for patients taking placebo in 20 studies with 4,125 participants. Common ADEs seen were somnolence, drowsiness, and sedation.
These occurred in 14% of participants in the gabapentin group versus 5% of those taking placebo. Data also showed gabapentin was associated with a higher incidence of dizziness (19% vs 5%), peripheral edema (7% vs 2.2%), and ataxia or gait disturbances (8.8% vs 1.1%).
The rate of serious events was similar between gabapentin and placebo groups. Twenty-two studies involving 4,448 patients reported on participant withdrawals due to ADEs, which occurred in 11% of patients taking gabapentin compared to 7.9% of those taking placebo.6
Postmarketing Abuse
Postmarketing reports have described symptoms of agitation, confusion, and disorientation upon abrupt withdrawal of gabapentin. Cases usually involve other potentiating factors, such as the use of higher than recommended doses for unapproved indications, a history of poly-substance abuse, or the use of gabapentin to relieve symptoms of withdrawal from other substances.1 In a study of postmortem toxicology, cases that tested positive for gabapentin or pregabalin were included to determine if abuse of these drugs contributed to the fatalities. Of the 13,766 cases investigated, 0.31% were positive for gabapentin. Of the gabapentin cases, 18.6% were considered abuse, and 4.7% were poisonings. An overwhelming majority of abuse cases (87.5%) also involved opioid intoxication, and 100% involved alcohol and/or opioids. In addition, a greater number of pregabalin cases were designated as abuse cases than gabapentin cases (48.1% vs 18.6%, respectively).7
Conclusion
Gabapentin has sufficient evidence showing its efficacy and safety in treating neuropathic pain. Effective treatment doses of gabapentin for neuropathic pain tend to be higher compared to effective treatment doses for other conditions. Gabapentin is a relatively safe medication. The most prevalent effects seen are drowsiness, somnolence, and sedation. It is necessary to start at lower doses of gabapentin and titrate up to a therapeutic dose. Ataxia and somnolence appear to exhibit a positive dose-response relationship; therefore, titrating the dose of gabapentin may help manage possible ADEs.
