Gabapentin Dosing for Neuropathic Pain
For treating neuropathic pain with gabapentin, start at 100-300 mg at bedtime or 300 mg three times daily, then gradually titrate to an effective dose of 900-3600 mg/day in divided doses, with most patients requiring 1800-3600 mg/day for optimal pain relief. 1, 2
Initial Dosing and Titration
- Start gabapentin at 100-300 mg at bedtime on day 1, then increase to 600 mg/day (300 mg twice daily) on day 2, and 900 mg/day (300 mg three times daily) on day 3 1
- Gradually increase the dose as needed for pain relief, with most patients requiring 1800-3600 mg/day 1, 3
- Administer in three divided doses per day, with the maximum time between doses not exceeding 12 hours 1
- Slower titration may be necessary for elderly patients or those who are medically frail to minimize adverse effects 4, 5
Effective Dosing Range
- Clinical studies have demonstrated efficacy across a dose range of 1800-3600 mg/day, with comparable effects throughout this range 1, 6
- For postherpetic neuralgia, 32% of patients achieve substantial pain relief (at least 50% reduction) with gabapentin at doses of 1200 mg/day or greater compared to 17% with placebo 6
- For diabetic neuropathy, 38% of patients achieve substantial pain relief with gabapentin at doses of 1200 mg/day or greater compared to 21% with placebo 6
Dosage Adjustment in Special Populations
- In patients with renal impairment, dose adjustment is required based on creatinine clearance 1:
- CrCl ≥60 mL/min: 900-3600 mg/day in three divided doses
- CrCl 30-59 mL/min: 400-1400 mg/day in two divided doses
- CrCl 15-29 mL/min: 200-700 mg/day as a single daily dose
- CrCl <15 mL/min: 100-300 mg/day as a single daily dose
- Elderly patients should receive lower starting doses with careful titration due to higher likelihood of decreased renal function 1, 4
Side Effects and Monitoring
- Common adverse effects include dizziness (19%), somnolence (14%), peripheral edema (7%), and gait disturbance (14%) 6
- Adverse events are typically mild to moderate and usually subside within approximately 10 days from treatment initiation 3
- Approximately 63% of patients on gabapentin experience at least one adverse event compared to 49% on placebo 6
- Adverse event withdrawals are more common with gabapentin (11%) than with placebo (8.2%) 6
Clinical Pearls
- Gabapentin can be administered with or without food 1
- If the dose needs to be reduced or discontinued, this should be done gradually over a minimum of 1 week to avoid withdrawal symptoms 1
- For patients with multiple types of neuropathic pain symptoms (allodynia, burning pain, shooting pain, hyperalgesia), gabapentin has shown efficacy across these various manifestations 7
- The effective dose should be individualized based on patient response and tolerability 3
- Gabapentin works by inhibiting the release of glutamate in the spinal cord dorsal horn, which is a key mechanism for its pain-relieving effects 8
Comparison with Pregabalin
- Pregabalin has linear pharmacokinetics compared to gabapentin's nonlinear absorption, making pregabalin dosing more predictable 5
- Maximum dose of gabapentin is 3600 mg/day compared to 600 mg/day for pregabalin 4, 5
- When switching from gabapentin to pregabalin, the recommended starting dose of pregabalin is 50 mg three times daily or 75 mg twice daily 4