NEURONTIN

The active ingredient in NEURONTIN capsules, tablets, and oral solution 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 NEURONTIN capsule contains 100 mg, 300 mg, or 400 mg of gabapentin and the following inactive ingredients: cornstarch, FD&C Blue No. 2, gelatin, lactose, red iron oxide (400 mg only), talc, titanium dioxide, and yellow iron oxide (300 mg and 400 mg only). Each NEURONTIN tablet contains 600 mg or 800 mg of gabapentin and the following inactive ingredients: candelilla wax, copovidone, cornstarch, hydroxypropyl cellulose, magnesium stearate, poloxamer 407, and talc. NEURONTIN oral solution contains 250 mg of gabapentin per 5 mL (50 mg per mL) and the following inactive ingredients: artificial cool strawberry anise flavor, glycerin, purified water, and xylitol. structural formula of gabapentin

NEURONTIN ® is 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 NEURONTIN is 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 )

• Postherpetic Neuralgia ( 2.1 ) o Dose can be titrated up as needed to a dose of 1800 mg/day o Day 1: Single 300 mg dose o Day 2: 600 mg/day (i.e., 300 mg two times a day) o Day 3: 900 mg/day (i.e., 300 mg three times a day) • Epilepsy with Partial Onset Seizures ( 2.2 ) o 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 o 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, NEURONTIN 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 NEURONTIN is 300 mg to 600 mg three times a day. Dosages up to 2400 mg/day have been administered 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. Administer NEURONTIN three times a day using 300 mg or 400 mg capsules, or 600 mg or 800 mg tablets. 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 NEURONTIN in patients 3 to 4 years of age is 40 mg/kg/day, given in three divided doses. The recommended maintenance dose of NEURONTIN in patients 5 to 11 years of age is 25 mg/kg/day to 35 mg/kg/day, given in three divided doses. NEURONTIN 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 administered 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 dosing recommendations above for effective doses in each indication): TABLE 1. NEURONTIN Dosage Based on Renal Function TID = Three times a day; BID = Two times a day; QD = Single daily dose Renal Function Creatinine Clearance (mL/min) Total Daily Dose Range (mg/day) Dose Regimen (mg) ≥ 60 900 to 3600 300 TID 400 TID 600 TID 800 TID 1200 TID >30 to 59 400 to 1400 200 BID 300 BID 400 BID 500 BID 700 BID >15 to 29 200 to 700 200 QD 300 QD 400 QD 500 QD 700 QD 15 For patients with creatinine clearance <15 mL/min, reduce daily dose in proportion to creatinine clearance (e.g., patients with a creatinine clearance of 7.5 mL/min should receive one-half the daily dose that patients with a creatinine clearance of 15 mL/min receive). 100 to 300 100 QD 125 QD 150 QD 200 QD 300 QD Post-Hemodialysis Supplemental Dose (mg) Patients on hemodialysis should receive maintenance doses based on estimates of creatinine clearance as indicated in the upper portion of the table and a supplemental post-hemodialysis dose administered after each 4 hours of hemodialysis as indicated in the lower portion of the table. Hemodialysis 125 150 200 250 350 Creatinine clearance (CLCr) is difficult to measure in outpatients. In patients with stable renal function, creatinine clearance can be reasonably well estimated using the equation of Cockcroft and Gault: The use of NEURONTIN in patients less than 12 years of age with compromised renal function has not been studied. the equation of Cockcroft and Gault 2.4 Dosage in Elderly 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. 2.5 Administration Information Administer NEURONTIN orally with or without food. NEURONTIN capsules should be swallowed whole with water. Inform patients that, should they divide the scored 600 mg or 800 mg NEURONTIN tablet in order to administer a half-tablet, they should take the unused half-tablet as the next dose. Half-tablets not used within 28 days of dividing the scored tablet should be discarded. If the NEURONTIN dose is reduced, discontinued, or substituted with an alternative medication, this should be done gradually over a minimum of 1 week (a longer period may be needed at the discretion of the prescriber).

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

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 Warnings and Precautions (5.4) ] • Suicidal Behavior and Ideation [see Warnings and Precautions (5.5) ] • Increased Risk of Seizures and Other Adverse Reactions with Abrupt or Rapid Discontinuation [see Warnings and Precautions (5.6) ] • Status Epilepticus [see Warnings and Precautions (5.7) ] • Respiratory Depression [see Warnings and Precautions (5.8) ] • Neuropsychiatric Adverse Reactions (Pediatric Patients 3 to 12 Years of Age) [see Warnings and Precautions (5.9) ] 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 Viatris at 1-877-446-3679 (1-877-4-INFO-RX) or FDA at 1-800-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 NEURONTIN 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 NEURONTIN 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 NEURONTIN-treated patients were dizziness, somnolence, and nausea. Table 3 lists adverse reactions that occurred in at least 1% of NEURONTIN-treated patients with postherpetic neuralgia participating in placebo-controlled trials and that were numerically more frequent in the NEURONTIN group than in the placebo group. TABLE 3. Adverse Reactions in Pooled Placebo-Controlled Trials in Postherpetic Neuralgia NEURONTIN 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 NEURONTIN 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 NEURONTIN in combination with other antiepileptic drugs in pediatric patients 3 to 12 years of age, not seen at an equal frequency among placebo-treated patients, were viral infection, fever, nausea and/or vomiting, somnolence, and hostility [see Warnings and Precautions (5.9) ] . Approximately 7% of the 2074 patients >12 years of age and approximately 7% of the 449 pediatric patients 3 to 12 years of age who received NEURONTIN in premarketing clinical trials discontinued treatment because of an adverse reaction. The adverse reactions most commonly associated with withdrawal in patients >12 years of age were somnolence (1.2%), ataxia (0.8%), fatigue (0.6%), nausea and/or vomiting (0.6%), and dizziness (0.6%). The adverse reactions most commonly associated with withdrawal in pediatric patients were emotional lability (1.6%), hostility (1.3%), and hyperkinesia (1.1%). Table 4 lists adverse reactions that occurred in at least 1% of NEURONTIN-treated patients >12 years of age with epilepsy participating in placebo-controlled trials and were numerically more common in the NEURONTIN group. In these studies, either NEURONTIN or placebo was added to the patient’s current antiepileptic drug therapy. TABLE 4. Adverse Reactions in Pooled Placebo-Controlled Add-On Trials in Epilepsy Patients >12 Years of Age NEURONTIN Plus background antiepileptic drug therapy N=543 % Placebo N=378 % Body as a Whole Fatigue 11 5 Increased weight 3 2 Back pain 2 1 Peripheral edema 2 1 Cardiovascular Vasodilatation 1 0 Digestive System Dyspepsia 2 1 Dry mouth or throat 2 1 Constipation 2 1 Dental abnormalities 2 0 Nervous System Somnolence 19 9 Dizziness 17 7 Ataxia 13 6 Nystagmus 8 4 Tremor 7 3 Dysarthria 2 1 Amnesia 2 0 Depression 2 1 Abnormal thinking 2 1 Abnormal coordination 1 0 Respiratory System Pharyngitis 3 2 Coughing 2 1 Skin and Appendages Abrasion 1 0 Urogenital System Impotence 2 1 Special Senses Diplopia 6 2 Amblyopia Amblyopia was often described as blurred vision. 4 1 Among the adverse reactions occurring at an incidence of at least 10% in NEURONTIN-treated patients, somnolence and ataxia appeared to exhibit a positive dose-response relationship. The overall incidence of adverse reactions and the types of adverse reactions seen were similar among men and women treated with NEURONTIN. The incidence of adverse reactions increased slightly with increasing age in patients treated with either NEURONTIN or placebo. Because only 3% of patients (28/921) in placebo-controlled studies were identified as nonwhite (black or other), there are insufficient data to support a statement regarding the distribution of adverse reactions by race. Table 5 lists adverse reactions that occurred in at least 2% of NEURONTIN-treated patients, age 3 to 12 years of age with epilepsy participating in placebo-controlled trials, and which were numerically more common in the NEURONTIN group. TABLE 5. Adverse Reactions in a Placebo-Controlled Add-On Trial in Pediatric Epilepsy Patients Age 3 to 12 Years NEURONTIN Plus background antiepileptic drug therapy N=119 % Placebo N=128 % Body as a Whole Viral infection 11 3 Fever 10 3 Increased weight 3 1 Fatigue 3 2 Digestive System Nausea and/or vomiting 8 7 Nervous System Somnolence 8 5 Hostility 8 2 Emotional lability 4 2 Dizziness 3 2 Hyperkinesia 3 1 Respiratory System Bronchitis 3 1 Respiratory infection 3 1 Other reactions in more than 2% of pediatric patients 3 to 12 years of age but equally or more frequent in the placebo group included: pharyngitis, upper respiratory infection, headache, rhinitis, convulsions, diarrhea, anorexia, coughing, and otitis media. 6.2 Postmarketing Experience The following adverse reactions have been identified during postmarketing use of NEURONTIN. Because these reactions are reported voluntarily from a population of uncertain size, it is not always possible to reliably estimate their frequency or establish a causal relationship to drug exposure. Hepatobiliary Disorders: jaundice Investigations: elevated creatine kinase, elevated liver function tests Metabolism and Nutrition Disorders: hyponatremia Musculoskeletal and Connective Tissue Disorder: rhabdomyolysis Nervous System Disorders: movement disorder Psychiatric Disorders: agitation Reproductive System and Breast Disorders: breast enlargement, changes in libido, ejaculation disorders and anorgasmia Skin and Subcutaneous Tissue Disorders: angioedema [see Warnings and Precautions (5.2) ] , bullous pemphigoid, erythema multiforme, Stevens-Johnson syndrome. There are postmarketing reports of life-threatening or fatal respiratory depression in patients taking NEURONTIN with opioids or other CNS depressants, or in the setting of underlying respiratory impairment [see Warnings and Precautions (5.8) ] . There are postmarketing reports of withdrawal symptoms after discontinuation of gabapentin. Reported adverse reactions include, but are not limited to, seizures, depression, suicidal ideation and behavior, agitation, confusion, disorientation, psychotic symptoms, anxiety, insomnia, nausea, pain, sweating, tremor, headache, dizziness, and malaise [see Warnings and Precautions (5.6) ] .

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 (5.8) ] . Hydrocodone Coadministration of NEURONTIN with hydrocodone decreases hydrocodone exposure [see Clinical Pharmacology (12.3) ] . The potential for alteration in hydrocodone exposure and effect should be considered when NEURONTIN 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. Drug Interactions • In Vitro Studies In vitro studies were conducted to investigate the potential of gabapentin to inhibit the major cytochrome P450 enzymes (CYP1A2, CYP2A6, CYP2C9, CYP2C19, CYP2D6, CYP2E1, and CYP3A4) that mediate drug and xenobiotic metabolism using isoform selective marker substrates and human liver microsomal preparations. Only at the highest concentration tested (171 mcg/mL; 1 mM) was a slight degree of inhibition (14% to 30%) of isoform CYP2A6 observed. No inhibition of any of the other isoforms tested was observed at gabapentin concentrations up to 171 mcg/mL (approximately 15 times the C max at 3600 mg/day). • In Vivo Studies The drug interaction data described in this section were obtained from studies involving healthy adults and adult patients with epilepsy. Phenytoin In a single (400 mg) and multiple dose (400 mg three times a day) study of NEURONTIN in epileptic patients (N=8) maintained on phenytoin monotherapy for at least 2 months, gabapentin had no effect on the steady-state trough plasma concentrations of phenytoin and phenytoin had no effect on gabapentin pharmacokinetics. Carbamazepine Steady-state trough plasma carbamazepine and carbamazepine 10, 11 epoxide concentrations were not affected by concomitant gabapentin (400 mg three times a day; N=12) administration. Likewise, gabapentin pharmacokinetics were unaltered by carbamazepine administration. Valproic Acid The mean steady-state trough serum valproic acid concentrations prior to and during concomitant gabapentin administration (400 mg three times a day; N=17) were not different and neither were gabapentin pharmacokinetic parameters affected by valproic acid. Phenobarbital Estimates of steady-state pharmacokinetic parameters for phenobarbital or gabapentin (300 mg three times a day; N=12) are identical whether the drugs are administered alone or together. Naproxen Coadministration (N=18) of naproxen sodium capsules (250 mg) with NEURONTIN (125 mg) appears to increase the amount of gabapentin absorbed by 12% to 15%. Gabapentin had no effect on naproxen pharmacokinetic parameters. These doses are lower than the therapeutic doses for both drugs. The magnitude of interaction within the recommended dose ranges of either drug is not known. Hydrocodone Coadministration of NEURONTIN (125 to 500 mg; N=48) decreases hydrocodone (10 mg; N=50) C max and AUC values in a dose-dependent manner relative to administration of hydrocodone alone; C max and AUC values are 3% to 4% lower, respectively, after administration of 125 mg NEURONTIN and 21% to 22% lower, respectively, after administration of 500 mg NEURONTIN. The mechanism for this interaction is unknown. Hydrocodone increases gabapentin AUC values by 14%. The magnitude of interaction at other doses is not known. Morphine A literature article reported that when a 60 mg controlled-release morphine capsule was administered 2 hours prior to a 600 mg NEURONTIN capsule (N=12), mean gabapentin AUC increased by 44% compared to gabapentin administered without morphine. Morphine pharmacokinetic parameter values were not affected by administration of NEURONTIN 2 hours after morphine. The magnitude of interaction at other doses is not known. Cimetidine In the presence of cimetidine at 300 mg four times a day (N=12), the mean apparent oral clearance of gabapentin fell by 14% and creatinine clearance fell by 10%. Thus, cimetidine appeared to alter the renal excretion of both gabapentin and creatinine, an endogenous marker of renal function. This decrease in excretion of gabapentin by cimetidine is not expected to be of clinical importance. The effect of gabapentin on cimetidine was not evaluated. Oral Contraceptive Based on AUC and half-life, multiple-dose pharmacokinetic profiles of norethindrone and ethinyl estradiol following administration of tablets containing 2.5 mg of norethindrone acetate and 50 mcg of ethinyl estradiol were similar with and without coadministration of gabapentin (400 mg three times a day; N=13). The C max of norethindrone was 13% higher when it was coadministered with gabapentin; this interaction is not expected to be of clinical importance. Antacid (Maalox ® ) (aluminum hydroxide, magnesium hydroxide) Antacid (Maalox ® ) containing magnesium and aluminum hydroxides reduced the mean bioavailability of gabapentin (N=16) by about 20%. This decrease in bioavailability was about 10% when gabapentin was administered 2 hours after Maalox. Probenecid Probenecid is a blocker of renal tubular secretion. Gabapentin pharmacokinetic parameters without and with probenecid were comparable. This indicates that gabapentin does not undergo renal tubular secretion by the pathway that is blocked by probenecid.