Gabapentin

FDA Drug Information • Also known as: Gaba 300-Ezs, Gabapentin, Gabarone, Gralise, Neurontin, Relgaabi

Brand Names: Gaba 300-Ezs, Gabapentin, Gabarone, Gralise, Neurontin, Relgaabi
Route: ORAL
Dosage Form: SOLUTION
Product Type: HUMAN PRESCRIPTION DRUG

Description

11 DESCRIPTION The active ingredient in Gabapentin Capsules USP is gabapentin, which has the chemical name 1-(aminomethyl)cyclohexaneacetic acid. The molecular formula of gabapentin is C 9 H 17 NO 2 and the molecular weight is 171.24. The structural formula of gabapentin is: Gabapentin is a white to off-white crystalline solid with a pK a1 of 3.7 and a pK a2 of 10.7. It is freely soluble in water and both basic and acidic aqueous solutions. The log of the partition coefficient (n-octanol/0.05M phosphate buffer) at pH 7.4 is –1.25. Each Gabapentin capsule contains 100 mg, 300 mg, or 400 mg of gabapentin and the following inactive ingredients: Pregelatinized Maize starch, talc, gelatin, titanium dioxide, yellow iron oxide (300 mg and 400 mg only), and red iron oxide (300 mg and 400 mg only), black iron oxide (300 mg and 400 mg only). Ingredients of Imprinting Ink( Black SW-9049) are Black Iron Oxide NF(E 172), Butyl Alcohol NF, Dehydrated Alcohol USP, Isopropyl Alcohol USP, Potassium Hydroxide NF, Propylene Glycol USP, Shellac NF, and Strong Ammonia Solution NF.

What Is Gabapentin Used For?

1 INDICATIONS AND USAGE Gabapentin Capsules, USP are indicated for: Management of postherpetic neuralgia in adults Adjunctive therapy in the treatment of partial onset seizures, with and without secondary generalization, in adults and pediatric patients 3 years and older with epilepsy Gabapentin Capsules, USP are indicated for Postherpetic neuralgia in adults (1) Adjunctive therapy in the treatment of partial onset seizures, with and without secondary generalization, in adults and pediatric patients 3 years and older with epilepsy (1)

Dosage and Administration

2 DOSAGE AND ADMlNlSTRATION Postherpetic Neuralgia (2.1) Dose can be titrated up as needed to a dose of 1800 mg/day Day 1: Single 300 mg dose Day 2: 600 mg/day (i.e., 300 mg two times a day) Day 3: 900 mg/day (i.e., 300 mg three times a day) Epilepsy with Partial Onset Seizures (2.2) Patients 12 years of age and older: starting dose is 300 mg three times daily; may be titrated up to 600 mg three times daily Patients 3 to 11 years of age: starting dose range is 10 to 15 mg/kg/day, given in three divided doses; recommended dose in patients 3 to 4 years of age is 40 mg/kg/day, given in three divided doses; the recommended dose in patients 5 to 11 years of age is 25 to 35 mg/kg/day, given in three divided doses. The recommended dose is reached by upward titration over a period of approximately 3 days Dose should be adjusted in patients with reduced renal function ( 2.3 , 2.4 ) 2.1 Dosage for Postherpetic Neuralgia In adults with postherpetic neuralgia, Gabapentin may be initiated on Day 1 as a single 300 mg dose, on Day 2 as 600 mg/day (300 mg two times a day), and on Day 3 as 900 mg/day (300 mg three times a day). The dose can subsequently be titrated up as needed for pain relief to a dose of 1800 mg/day (600 mg three times a day). In clinical studies, efficacy was demonstrated over a range of doses from 1800 mg/day to 3600 mg/day with comparable effects across the dose range; however, in these clinical studies, the additional benefit of using doses greater than 1800 mg/day was not demonstrated 2.2 Dosage for Epilepsy with Partial Onset Seizures Patients 12 years of age and above The starting dose is 300 mg three times a day. The recommended maintenance dose of Gabapentin is 300 mg to 600 mg three times a 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. Administer Gabapentin three times a day using 300 mg or 400 mg capsules. The maximum time between doses should not exceed 12 hours. Pediatric Patients Age 3 to 11 years The starting dose range is 10 mg/kg/day to 15 mg/kg/day, given in three divided doses, and the recommended maintenance dose reached by upward titration over a period of approximately 3 days. The recommended maintenance dose of Gabapentin in patients 3 to 4 years of age is 40 mg/kg/day, given in three divided doses. The recommended maintenance dose of Gabapentin in patients 5 to 11 years of age is 25 mg/kg/day to 35 mg/kg/day, given in three divided doses. Gabapentin may be administered as the capsule 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. 2.3 Dosage Adjustment in Patients with Renal Impairment Dosage adjustment in patients 12 years of age and older with renal impairment or undergoing hemodialysis is recommended, as follows (see...

Side Effects (Adverse Reactions)

6 ADVERSE REACTIONS The following serious adverse reactions are discussed in greater detail in other sections: Drug Reaction with Eosinophilia and Systemic Symptoms (DRESS)/Multiorgan Hypersensitivity [see Warnings and Precautions (5.1) ] Anaphylaxis and Angioedema [see Warnings and Precautions (5.2) ] Somnolence/Sedation and Dizziness [see see Warnings and Precautions (5.4) ] Withdrawal Precipitated Seizure, Status Epilepticus [see see Warnings and Precautions (5.5) ] Suicidal Behavior and Ideation [see see Warnings and Precautions (5.6) ] Respiratory Depression [see Warnings and Precautions (5.7) ] Neuropsychiatric Adverse Reactions (Pediatric Patients 3 to 12 Years of Age) [ see Warnings and Precautions (5.8) ] Sudden and Unexplained Death in Patients with Epilepsy [see Warnings and Precautions (5.10) ] Most common adverse reactions (incidence ≥8% and at least twice that for placebo) were: Postherpetic neuralgia: Dizziness, somnolence, and peripheral edema (6.1) Epilepsy in patients >12 years of age: Somnolence, dizziness, ataxia, fatigue, and nystagmus (6.1) Epilepsy in patients 3 to 12 years of age: Viral infection, fever, nausea and/or vomiting, somnolence, and hostility (6.1) To report SUSPECTED ADVERSE REACTIONS, contact ACI HealthcareUSA, Inc. at 1-888-802-1213 or www.acihealthcareusa.com or FDA at1-800-FDA-1088 or www.fda.gov/medwatch. 6.1 Clinical Trials Experience Because clinical trials are conducted under widely varying conditions, adverse reaction rates observed in the clinical trials of a drug cannot be directly compared to rates in the clinical trials of another drug and may not reflect the rates observed in practice. Postherpetic Neuralgia The most common adverse reactions associated with the use of Gabapentin in adults, not seen at an equivalent frequency among placebo-treated patients, were dizziness, somnolence, and peripheral edema. In the 2 controlled trials in postherpetic neuralgia, 16% of the 336 patients who received Gabapentin and 9% of the 227 patients who received placebo discontinued treatment because of an adverse reaction. The adverse reactions that most frequently led to withdrawal in Gabapentin-treated patients were dizziness, somnolence, and nausea. Table 3 lists adverse reactions that occurred in at least 1% of Gabapentin-treated patients with postherpetic neuralgia participating in placebo-controlled trials and that were numerically more frequent in the Gabapentin group than in the placebo group. TABLE 3. Adverse Reactions in Pooled Placebo-Controlled Trials in Postherpetic Neuralgia Gabapentin N=336 % Placebo N=227 % Body as a Whole Asthenia 6 5 Infection 5 4 Accidental injury 3 1 Digestive System Diarrhea 6 3 Dry mouth 5 1 Constipation 4 2 Nausea 4 3 Vomiting 3 2 Metabolic and Nutritional Disorders Peripheral edema 8 2 Weight gain 2 0 Hyperglycemia 1 0 Nervous System Dizziness 28 8 Somnolence 21 5 Ataxia 3 0 Abnormal thinking 3 0 Abnormal gait 2 0 Incoordination 2 0 Respiratory System Pharyngitis 1 0 Special Senses Amblyopia Reported as blurred vision 3 1 Conjunctivitis 1 0 Diplopia 1 0 Otitis media 1 0 Other reactions in more than 1% of patients but equally or more frequent in the placebo group included pain, tremor, neuralgia, back pain, dyspepsia, dyspnea, and flu syndrome. There were no clinically important differences between men and women in the types and incidence of adverse reactions. Because there were few patients whose race was reported as other than white, there are insufficient data to support a statement regarding the distribution of adverse reactions by race. Epilepsy with Partial Onset Seizures (Adjunctive Therapy) The most common adverse reactions with Gabapentin in combination with other antiepileptic drugs in patients >12 years of age, not seen at an equivalent frequency among placebo-treated patients, were somnolence, dizziness, ataxia, fatigue, and nystagmus. The most common adverse reactions with gabapentin in combination with other antiepileptic drugs in pediatric...

Drug Interactions

7 DRUG INTERACTIONS Concentrations increased by morphine; may need dose adjustment (5.4, 7.1 ) 7.1 Opioids Respiratory depression and sedation, sometimes resulting in death, have been reported following coadministration of gabapentin with opioids (e.g., morphine, hydrocodone, oxycodone, buprenorphine) [ see Warnings and Precautions (5.7) ]. Hydrocodone Coadministration of gabapentin with hydrocodone decreases hydrocodone exposure [ see Clinical Pharmacology (12.3) ]. The potential for alteration in hydrocodone exposure and effect should be considered when gabapentin is started or discontinued in a patient taking hydrocodone. Morphine When gabapentin is administered with morphine, patients should be observed for signs of CNS depression, such as somnolence, sedation and respiratory depression [see Clinical Pharmacology (12.3) ]. 7.2 Other Antiepileptic Drugs Gabapentin is not appreciably metabolized nor does it interfere with the metabolism of commonly coadministered antiepileptic drugs [ see Clinical Pharmacology (12.3) ] . 7.3 Maalox ® (aluminum hydroxide, magnesium hydroxide) The mean bioavailability of gabapentin was reduced by about 20% with concomitant use of an antacid (Maalox ® ) containing magnesium and aluminum hydroxides. It is recommended that gabapentin be taken at least 2 hours following Maalox administration [see Clinical Pharmacology (12.3)] . 7.4 Drug/Laboratory Test Interactions Because false positive readings were reported with the Ames N-Multistix SG ® dipstick test for urinary protein when gabapentin was added to other antiepileptic drugs, the more specific sulfosalicylic acid precipitation procedure is recommended to determine the presence of urine protein. 7.1 Opioids Respiratory depression and sedation, sometimes resulting in death, have been reported following coadministration of gabapentin with opioids (e.g., morphine, hydrocodone, oxycodone, buprenorphine) [ see Warnings and Precautions (5.7) ]. Hydrocodone Coadministration of gabapentin with hydrocodone decreases hydrocodone exposure [ see Clinical Pharmacology (12.3) ]. The potential for alteration in hydrocodone exposure and effect should be considered when gabapentin is started or discontinued in a patient taking hydrocodone. Morphine When gabapentin is administered with morphine, patients should be observed for signs of CNS depression, such as somnolence, sedation and respiratory depression [see Clinical Pharmacology (12.3) ]. 7.2 Other Antiepileptic Drugs Gabapentin is not appreciably metabolized nor does it interfere with the metabolism of commonly coadministered antiepileptic drugs [ see Clinical Pharmacology (12.3) ] . 7.3 Maalox ® (aluminum hydroxide, magnesium hydroxide) The mean bioavailability of gabapentin was reduced by about 20% with concomitant use of an antacid (Maalox ® ) containing magnesium and aluminum hydroxides. It is recommended that gabapentin be taken at least 2 hours following Maalox administration [see Clinical Pharmacology (12.3)] . 7.4...

Contraindications

4 CONTRAINDICATIONS Gabapentin is contraindicated in patients who have demonstrated hypersensitivity to the drug or its ingredients. Known hypersensitivity to gabapentin or its ingredients (4)

Pregnancy and Breastfeeding

8.1 Pregnancy Pregnancy Exposure Registry There is a pregnancy exposure registry that monitors pregnancy outcomes in women exposed to antiepileptic drugs (AEDs), such as Gabapentin, during pregnancy. Encourage women who are taking Gabapentin during pregnancy to enroll in the North American Antiepileptic Drug (NAAED) Pregnancy Registry by calling the toll free number 1-888-233-2334 or visiting http://www.aedpregnancyregistry.org/. Risk Summary There are no adequate data on the developmental risks associated with the use of Gabapentin in pregnant women. In nonclinical studies in mice, rats, and rabbits, gabapentin was developmentally toxic (increased fetal skeletal and visceral abnormalities, and increased embryofetal mortality) when administered to pregnant animals at doses similar to or lower than those used clinically [see Data]. In the U.S. general population, the estimated background risk of major birth defects and miscarriage in clinically recognized pregnancies is 2 to 4% and 15 to 20%, respectively. The background risk of major birth defects and miscarriage for the indicated population is unknown. Data Animal data When pregnant mice received oral doses of gabapentin (500, 1000, or 3000 mg/kg/day) during the period of organogenesis, embryofetal toxicity (increased incidences of skeletal variations) was observed at the two highest doses. The no-effect dose for embryofetal developmental toxicity in mice (500 mg/kg/day) is less than the maximum recommended human dose (MRHD) of 3600 mg on a body surface area (mg/m 2 ) basis. In studies in which rats received oral doses of gabapentin (500 to 2000 mg/kg/day) during pregnancy, adverse effect on offspring development (increased incidences of hydroureter and/or hydronephrosis) were observed at all doses. The lowest dose tested is similar to the MRHD on a mg/m 2 basis. When pregnant rabbits were treated with gabapentin during the period of organogenesis, an increase in embryofetal mortality was observed at all doses...

Overdosage

10 OVERDOSAGE Signs of acute toxicity in animals included ataxia, labored breathing, ptosis, sedation, hypoactivity, or excitation. Acute oral overdoses of gabapentin have been reported. Symptoms have included double vision, tremor, slurred speech, drowsiness, altered mental status, dizziness, lethargy, and diarrhea. Fatal respiratory depression has been reported with gabapentin overdose, alone and in combination with other CNS depressants. Gabapentin can be removed by hemodialysis. If overexposure occurs, call your poison control center at 1-800-222-1222.

How Supplied

16 HOW SUPPLIED/STORAGE AND HANDLING Gabapentin Capsules USP 300 mg capsules: Hard gelatin capsules with yellow opaque body with caramel opaque cap, imprinted with “AHD” on cap and “300” on body in black ink and filled with white to off-white powder. NDC: 71335-1093-8: 40 Capsules in a BOTTLE NDC: 71335-1093-1: 90 Capsules in a BOTTLE NDC: 71335-1093-2: 28 Capsules in a BOTTLE NDC: 71335-1093-3: 58 Capsules in a BOTTLE NDC: 71335-1093-4: 30 Capsules in a BOTTLE NDC: 71335-1093-5: 60 Capsules in a BOTTLE NDC: 71335-1093-6: 120 Capsules in a BOTTLE NDC: 71335-1093-7: 180 Capsules in a BOTTLE Store at 20° to 25° C (68° to 77° F); excursions permitted to 15° to 30°C (59° to B6°F). [See USP Controlled Room Temperature] Repackaged/Relabeled by: Bryant Ranch Prepack, Inc. Burbank, CA 91504

About This Information

This drug information is sourced from FDA-approved labeling via the openFDA database. It is intended for educational and reference purposes only. This is not medical advice. Always consult your healthcare provider before making decisions about medication. Drug information may be updated by the FDA; check with your pharmacist for the most current information.

What are side effects?

Side effects are unwanted reactions that can occur when taking a medication. They range from mild (headache, nausea) to severe (allergic reactions, organ damage). Not everyone experiences side effects, and severity varies. Report any concerning side effects to your doctor.

What are drug interactions?

Drug interactions occur when a medication is affected by another drug, food, or supplement. Interactions can make medications less effective or cause dangerous side effects. Always tell your doctor about all medications and supplements you take.