What is the recommended dosing regimen for gabapentin (gabapentin) in an older adult with post-stroke neuropathic symptoms, specifically neuralgia?

Gabapentin Dosing for Post-Stroke Neuropathic Pain in Older Adults

Start gabapentin at 100 mg once daily at bedtime in this older adult, then titrate slowly by 100 mg every 3-7 days to reach a target dose of 1800 mg/day divided three times daily (600 mg TID), with a maximum of 3600 mg/day if needed for adequate pain control. 1, 2

Initial Dosing Strategy for Older Adults

For elderly patients with post-stroke neuropathic symptoms, use the lowest starting dose of 100-200 mg/day rather than the standard 300 mg starting dose. 1, 2 The American Geriatrics Society specifically recommends this conservative approach due to increased vulnerability to side effects including dizziness, somnolence, and mental clouding in older adults. 1

Day 1-3 Initiation

• Day 1: Start 100 mg at bedtime 2
• Day 2-3: Continue 100 mg at bedtime, monitor for tolerability 2
• Do not use the standard FDA-approved rapid titration (300 mg day 1,600 mg day 2,900 mg day 3) in elderly patients 3, 1

Titration Schedule

Increase the dose by 100-300 mg increments every 3-7 days as tolerated, with slower intervals (every 7 days) preferred in older adults. 1, 2 This contrasts with younger patients who may tolerate faster titration every 1-3 days. 2

Suggested Titration Path

• Week 1: 100 mg at bedtime 2
• Week 2: 100 mg twice daily (200 mg/day) 2
• Week 3: 100 mg three times daily (300 mg/day) 2
• Week 4: 200 mg three times daily (600 mg/day) 2
• Week 5-6: 300 mg three times daily (900 mg/day) 2
• Continue increasing by 300 mg every 3-7 days until reaching 1800 mg/day (600 mg TID) 2

Target Therapeutic Dose

The minimum effective dose for most neuropathic pain conditions is 1800 mg/day (600 mg three times daily), with a maximum of 3600 mg/day (1200 mg TID) if needed. 2, 3 The American Academy of Neurology emphasizes that three-times-daily dosing is essential due to gabapentin's saturable, nonlinear absorption pharmacokinetics. 2

Moderate-quality evidence shows that 32-38% of patients achieve at least 50% pain reduction with gabapentin 1800-3600 mg/day, compared to 17-21% with placebo. 4, 5 However, effective doses in older adults may be lower than these standard ranges. 1

Critical Renal Dosing Adjustments

Mandatory dose reduction is required based on creatinine clearance, as gabapentin is eliminated primarily by renal excretion. 2, 3 This is particularly important in older adults who commonly have age-related decline in renal function. 1

Renal Dosing Table (FDA-Approved) 3

• CrCl ≥60 mL/min: 300-1200 mg three times daily (standard dosing)
• CrCl 30-59 mL/min: 200-700 mg twice daily
• CrCl 15-29 mL/min: 200-700 mg once daily
• CrCl <15 mL/min: 100-300 mg once daily
• Hemodialysis: Maintenance dose based on CrCl + supplemental 125-350 mg post-dialysis

Calculate creatinine clearance using the Cockcroft-Gault equation before initiating therapy. 3 Do not rely on serum creatinine alone in elderly patients, as they may have reduced muscle mass leading to falsely reassuring creatinine values despite significant renal impairment. 3

Duration of Adequate Trial

Allow a minimum of 2 months for an adequate therapeutic trial: 3-8 weeks for titration plus 2 weeks at maximum tolerated dose. 2 Efficacy for neuropathic pain develops gradually over several weeks, not immediately. 2 Do not declare treatment failure prematurely, as pain relief may take the full trial period to manifest. 2

Prescription Writing

Write the prescription as:

• Gabapentin 100 mg capsules
• Sig: Take 1 capsule by mouth at bedtime
• Dispense: #30 capsules
• Refills: 0 (require follow-up for titration)

Provide explicit written titration instructions to the patient, as gabapentin requires gradual dose escalation and cannot be started at the therapeutic dose. 2

Common Pitfalls to Avoid

Do not use once-daily or twice-daily dosing for standard gabapentin at therapeutic doses. 2 Three-times-daily administration is essential due to saturable absorption—the drug's bioavailability decreases at higher single doses. 2

Do not rush titration in elderly patients. 2 A retrospective population study of 110,184 older adults (mean age 76) found that initiating high-dose gabapentin (>600 mg/day) versus low-dose (≤600 mg/day) was associated with increased 30-day hospitalization with altered mental status (1.27% vs 1.06%, NNH 477). 6 While the absolute risk remains low, slower titration reduces fall risk from dizziness. 2

Do not discontinue abruptly. 2 Taper gradually over at least 1 week to avoid withdrawal symptoms including anxiety, insomnia, nausea, pain, and sweating. 2

Expected Adverse Effects

Counsel patients that 62% will experience at least one adverse event, most commonly dizziness (19%), somnolence (14%), peripheral edema (7%), and gait disturbance (9%). 4 These effects are typically mild to moderate and often transient, subsiding within approximately 10 days. 7, 8

Adverse event withdrawals occur in 11% of patients versus 8.2% with placebo (NNH 30). 4 However, serious adverse events (3.2%) are no more common than placebo (2.8%). 4

Monitoring Strategy

• Week 1-2: Assess tolerability, dizziness, somnolence, fall risk
• Week 4: Reassess pain scores, adjust dose if tolerated
• Week 8: Evaluate for at least 30% pain reduction (moderate benefit)
• Week 12: Final assessment for at least 50% pain reduction (substantial benefit)

If inadequate response after 2 months at maximum tolerated dose (up to 3600 mg/day), consider alternative or adjunctive therapy rather than continuing ineffective treatment. 2