Dosing Considerations: Because pms-GABAPENTIN is eliminated solely by renal excretion, dosage adjustments are recommended for patients with renal impairment (including elderly patients with declining renal function) and patients undergoing hemodialysis (see Special Patient Populations: Geriatrics and Renal Impairment (Table 5) as follows; Neurologic under Precautions).
Adults: pms-GABAPENTIN (gabapentin) is given orally with or without food.
Initial Dose: The starting dose is 300 mg three times a day.
Dose Range: The dose may be increased, depending on the response and tolerance of the patient, using 300 or 400 mg capsules, or 600 or 800 mg tablets 3 times a day up to 1,800 mg/day. In clinical trials, the effective dosage range was 900 to 1,800 mg/day, given 3 times a day using 300 mg or 400 mg capsules, or 600 mg or 800 mg tablets. Dosages up to 2,400 mg/day have been well tolerated in long-term open-label clinical studies. Doses of 3,600 mg/day have also been administered to a small number of patients for a relatively short duration and have been well tolerated.
Although data from clinical trials suggest that doses higher than 1,200 mg/day may have increased efficacy in some patients, higher doses may also increase the incidence of adverse events (see Dose-Related Treatment Emergent Adverse Events under Adverse Reactions).
Maintenance: Daily maintenance doses should be given in three equally divided doses, and the maximum time between doses in a three times daily schedule should not exceed 12 hours to prevent breakthrough convulsions. It is not necessary to monitor gabapentin plasma concentrations in order to optimize pms-GABAPENTIN therapy. Further, as there are no drug interactions with commonly used antiepileptic drugs, pms-GABAPENTIN may be used in combination with these drugs without concern for alteration of plasma concentrations of either gabapentin or other antiepileptic drugs.
Discontinuation of Treatment, Dose Reduction or Initiation of Adjunctive Antiepileptic Therapy: If pms-GABAPENTIN dose is reduced, discontinued or substituted with an alternate anticonvulsant or an alternate anticonvulsant is added to pms-GABAPENTIN therapy, this should be done gradually over a minimum of 1 week (a longer period may be needed at the discretion of the prescriber (see Psychiatric under Precautions).
Special Patient Populations: Geriatrics and Renal Impairment: Due to the primarily renal excretion of pms-GABAPENTIN, the following dosage adjustments are recommended for elderly patients with declining renal function, patients with renal impairment and patients undergoing hemodialysis (see Dosing Considerations as previously mentioned; Pharmacology: Pharmacokinetics: Special Populations and Conditions: Geriatrics, Renal Insufficiency, Hemodialysis under Actions). (See Table 5.)
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Pediatrics: pms-GABAPENTIN (gabapentin) is not indicated for use in children under 18 years of age (see Pediatrics (< 18 years of age) under Indications/Uses; Use in Children under Precautions).
Hepatic Impairment: Because gabapentin is not metabolized to a significant extent in humans, no studies have been performed in patients with hepatic impairment.
Missed Dose: Physicians should instruct their patients that if a dose is missed, the next one should be taken as soon as possible. However, if it is within 4 hours of the next dose, the missed dose is not to be taken and the patient should return to the regular dosing schedule. To avoid breakthrough convulsions the maximum time between doses should not exceed 12 hours.