Gabapentin Dosage and Administration
Gabapentin is given orally with or without food. Patients should be informed that, should they break the scored 600 mg or 800 mg 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 breaking the scored tablet should be discarded.
Gabapentin capsules should be swallowed whole with plenty of water.
If 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).
Postherpetic Neuralgia
In adults with postherpetic neuralgia, Gabapentin therapy 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.
Epilepsy with Partial Onset Seizures
Gabapentin is recommended for add-on therapy in patients 3 years of age and older. Effectiveness in pediatric patients below the age of 3 years has not been established.
Patients 12 years of age and above: The starting dose is 300 mg three times a day. The effective 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. Gabapentin should be administered 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 effective dose reached by upward titration over a period of approximately 3 days. The effective dose of Gabapentin in patients 3 to 4 years of age is 40 mg/kg/day, given in three divided doses. The effective 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.
It is not necessary to monitor Gabapentin plasma concentrations to optimize Gabapentin therapy. Further, because there are no significant pharmacokinetic interactions among Gabapentin and other commonly used antiepileptic drugs, the addition of Gabapentin does not alter the plasma levels of these drugs appreciably.
If Gabapentin is discontinued and/or an alternate anticonvulsant medication is added to the therapy, this should be done gradually over a minimum of 1 week.
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):
