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 tablets 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 tablets three times a day using 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 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 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.
2.3 Dosage Adjustment in Patients with Renal Impairment
Dosage adjustment in patients 12 years of age and older with compromised renal function or undergoing hemodialysis is recommended, as follows (see dosing recommendations above for effective doses in each indication):
TABLE 1. Gabapentin Tablets Dosage Based on Renal Function
Renal Function Creatinine Clearance
(mL/min)
Total Daily Dose Range
(mg/day)
Dose Regimen
(mg)
≥60
900-3600
300 TID
400 TID
600 TID
800 TID
1200 TID
>30-59
400-1400
200 BID
300 BID
400 BID
500 BID
700 BID
>15-29
200-700
200 QD
300 QD
400 QD
500 QD
700 QD
15a
100-300
100 QD
125 QD
150 QD
200 QD
300 QD
Post-Hemodialysis Supplemental Dose (mg)b
Hemodialysis
125b
150b
200b
250b
350b
TID = Three times a day; BID = Two times a day; QD = Single daily dose
a 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).
b 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.
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 gabapentin tablets in patients less than 12 years of age with compromised renal function has not been studied.
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 gabapentin orally with or without food.
Inform patients that, should they divide the scored 600 mg or 800 mg gabapentin 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 gabapentin 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).
