What is the recommended dose of gabapentin (Neurontin) for a 75-year-old female (YOF) with impaired renal function and neuropathic pain?

Gabapentin Dosing for a 75-Year-Old Female with Renal Failure and Neuropathic Pain

For a 75-year-old female with renal failure and neuropathic pain, gabapentin should be started at 100-300 mg once daily with careful titration based on creatinine clearance, not exceeding 300 mg daily for severe renal impairment. 1

Renal Dosing Considerations

Gabapentin is primarily eliminated through renal excretion, making dose adjustment essential in patients with renal impairment. The FDA-approved labeling provides specific guidance:

Dosing Based on Renal Function

Creatinine Clearance (mL/min)	Total Daily Dose Range (mg/day)	Dose Regimen
≥60	900-3600	300-1200 mg TID
>30-59	400-1400	200-700 mg BID
>15-29	200-700	200-700 mg QD
≤15	100-300	100-300 mg QD

For patients on hemodialysis, a supplemental post-hemodialysis dose should be administered after each 4 hours of hemodialysis 1.

Titration Schedule for Elderly Patients with Renal Impairment

1. Initial dose: Start with 100-300 mg at bedtime 2
2. Titration: Increase by 100-300 mg every 1-7 days as tolerated, with slower titration for elderly patients 2, 3
3. Maximum dose: Determined by creatinine clearance (see table above)
4. Duration of trial: 3-8 weeks for titration plus 2 weeks at maximum dose 2

Efficacy Considerations

Gabapentin has demonstrated efficacy for neuropathic pain with:

• NNT of 5.9 for at least 50% pain relief in diabetic neuropathy 4
• NNT of 6.7 for at least 50% pain relief in postherpetic neuralgia 4
• Doses of 900-1800 mg/day are effective for most patients with lower risk of adverse effects 3
• Higher doses (>1800 mg/day) provide minimal additional benefit while significantly increasing risk of adverse effects 3, 5

Common Adverse Effects in Elderly Patients

Patients should be monitored for:

• Dizziness (19% of patients) 4
• Somnolence (14%) 4
• Peripheral edema (7%) 4
• Gait disturbance (9%) 4

These side effects can be minimized by:

• Starting with lower dosages
• Titrating cautiously
• Taking medication with food
• Dividing the daily dose appropriately 3

Common Pitfalls to Avoid

1. Underdosing: Many clinicians prescribe doses much lower than those used in clinical trials 3
2. Overly rapid titration: Increases risk of adverse effects; slower titration improves tolerability 3
3. Failure to adjust for renal impairment: Can lead to increased risk of adverse effects 3, 6
4. Inadequate trial duration: An adequate trial requires 3-8 weeks for titration plus 2 weeks at maximum dose 2
5. Abrupt discontinuation: When discontinuing gabapentin, taper gradually over at least 1 week to avoid withdrawal symptoms 3, 1

Monitoring and Follow-up

• Assess efficacy after 3-8 weeks of titration plus 2 weeks at maximum dose
• Monitor renal function regularly
• Evaluate for adverse effects at each dose increase
• Consider alternative or adjunctive therapy if inadequate response after an adequate trial

For this 75-year-old female with renal failure, the focus should be on starting with a low dose, titrating slowly, and carefully monitoring both efficacy and adverse effects, with the maximum dose determined by her specific creatinine clearance level.