What is the maximum dose of gabapentin (Neurontin) to take at one time?

Maximum Dose of Gabapentin to Take at One Time

The maximum single dose of gabapentin is 1200 mg, while the maximum daily dose is 3600 mg, typically divided into three doses. 1, 2

Dosing Guidelines for Gabapentin

FDA-Approved Maximum Dosing

• For postherpetic neuralgia, the recommended maintenance dose is 1800 mg/day (600 mg three times a day), though clinical studies have demonstrated efficacy across doses from 1800-3600 mg/day 1
• For epilepsy in adults and patients 12 years and older, doses up to 2400 mg/day have been well tolerated in long-term studies, with 3600 mg/day administered for shorter durations 1
• The maximum time between doses should not exceed 12 hours to maintain therapeutic blood levels 1

Single Dose Considerations

• Gabapentin is typically initiated at lower doses (300 mg) and gradually titrated to minimize side effects 2
• When taking gabapentin for neuropathic pain, the maximum single dose is generally 1200 mg, as part of the maximum daily dose of 3600 mg divided into three doses 2
• Doses higher than 1200 mg at one time are not recommended due to decreased absorption and increased risk of adverse effects 3

Titration and Administration

• Initial dosing should start at 100-300 mg at bedtime or 100-300 mg three times daily 2
• Increase by 100-300 mg every 1-7 days as tolerated 2
• For neuropathic pain, treatment should be initiated at low dosages with gradual titration until pain relief, dose-limiting adverse effects, or the maximum dose of 3600 mg/day in 3 divided doses is reached 2
• An adequate trial of gabapentin for pain can require 2 months or more to determine full efficacy 2

Special Populations and Considerations

Renal Impairment

• Dosage adjustment is required in patients with compromised renal function 1
• For creatinine clearance ≥60 mL/min: standard dosing applies (up to 3600 mg/day) 1
• For creatinine clearance 30-59 mL/min: maximum 1400 mg/day 1
• For creatinine clearance 15-29 mL/min: maximum 700 mg/day 1
• For creatinine clearance <15 mL/min: maximum 300 mg/day 1

Elderly Patients

• Lower starting doses and slower titration are recommended due to increased likelihood of decreased renal function 2, 1
• Dose should be adjusted based on creatinine clearance values 1

Adverse Effects

• Common side effects include dizziness (19%), somnolence (14%), peripheral edema (7%), and gait disturbance (14%) 4
• Adverse events are more common with gabapentin (63%) than with placebo (49%) 4
• Adverse event withdrawals occur in approximately 11% of patients on gabapentin 4
• Side effects can be reduced by starting with lower dosages and titrating cautiously 2

Clinical Efficacy

• In postherpetic neuralgia, approximately 32% of patients achieve substantial pain relief (at least 50% reduction) with gabapentin at doses of 1200 mg daily or greater 4
• In diabetic neuropathy, about 38% of patients achieve substantial pain relief with gabapentin at doses of 1200 mg daily or greater 4
• Gabapentin's pharmacokinetics are nonlinear due to saturable absorption, which means higher single doses may not provide proportionally increased benefit 2, 5

Important Considerations

• Gabapentin should be taken with or without food 1
• If a dose is reduced, discontinued, or substituted with an alternative medication, this should be done gradually over a minimum of 1 week to avoid withdrawal symptoms 1
• For unexplained chronic cough, a therapeutic trial of gabapentin can be considered with dose escalation beginning at 300 mg once daily up to a maximum tolerable daily dose of 1800 mg in two divided doses 2

Remember that while the maximum single dose is 1200 mg, most patients will achieve optimal balance of efficacy and tolerability at lower doses, and individualized dosing based on response and side effects is essential for optimal outcomes.