What is the maximum recommended daily dose of gabapentin for a 72-year-old woman with normal renal function (estimated glomerular filtration rate ≈ 96 mL/min)?

Maximum Gabapentin Dose for 72-Year-Old Female with Normal Renal Function

For a 72-year-old woman with a GFR of 96 mL/min (normal renal function), the maximum recommended daily dose of gabapentin is 3600 mg/day, divided into three doses of 1200 mg each, with no renal dose adjustment required. 1

FDA-Approved Dosing Guidelines

The FDA label provides clear dosing parameters for patients with normal renal function (creatinine clearance ≥60 mL/min): 1

• Maximum daily dose: 3600 mg/day divided into three doses
• Standard therapeutic range: 900-3600 mg/day
• Dosing frequency: Three times daily (TID), with maximum 12-hour interval between doses
• No renal adjustment needed at GFR 96 mL/min

Standard Titration Protocol

For patients 12 years and older with normal renal function, the FDA recommends: 1

• Starting dose: 300 mg three times daily (900 mg/day total)
• Maintenance dose: 300-600 mg three times daily (900-1800 mg/day)
• Titration: Increase by 300 mg/day every 1-7 days as tolerated
• Target therapeutic dose: 1800 mg/day for most indications
• Doses up to 2400 mg/day have been well tolerated in long-term studies 1
• Doses of 3600 mg/day have been administered to smaller patient populations for shorter durations and were well tolerated 1

Age-Related Considerations

Although this patient has normal renal function, her age warrants cautious dosing: 1

• The FDA specifically states that elderly patients are more likely to have decreased renal function, requiring careful dose selection 1
• Consider starting at 100-300 mg at bedtime or three times daily, with slower titration 2
• Monitor closely for dose-dependent adverse effects including dizziness and sedation 2

Critical Evidence on Higher Doses in Elderly Patients

Recent population-based research raises important safety concerns about higher starting doses in older adults: 3

• A 2022 study of 74,084 older adults (median age 79 years) found that starting gabapentin at >300 mg/day was associated with a 27% increased risk of hospital visits for encephalopathy, falls, fractures, or respiratory depression within 30 days 3
• The absolute risk increase was 0.40% (number needed to harm = 250) 3
• This evidence suggests starting at ≤300 mg/day is safer in elderly patients, even with normal renal function 3

Optimal Therapeutic Dosing Strategy

Based on randomized controlled trial data: 4

• Initial dose: 900 mg/day (300 mg on day 1,600 mg on day 2,900 mg on day 3)
• Recommended therapeutic dose: 1800 mg/day for greater efficacy
• Maximum dose: Up to 3600 mg/day may be needed in some patients
• Doses of 1800-3600 mg/day were effective and well tolerated in clinical trials 4

Practical Dosing Algorithm for This Patient

Given the patient's age (72 years) but normal renal function (GFR 96), I recommend the following approach:

1. Start conservatively: 300 mg at bedtime for 2-3 days, then 300 mg twice daily for 2-3 days, then 300 mg three times daily (900 mg/day total) 1, 3

2. Titrate gradually: Increase by 300 mg/day every 3-7 days (slower than younger patients) 2

3. Target dose: 1800 mg/day (600 mg three times daily) for most indications 1, 4

4. Maximum allowable dose: 3600 mg/day (1200 mg three times daily) if needed for refractory symptoms and well tolerated 1

5. Monitor closely during titration for dizziness, sedation, confusion, and fall risk 2, 3

Common Pitfalls to Avoid

• Do not use MDRD or CKD-EPI equations for gabapentin dosing—these methods overestimate renal function in elderly patients and lead to inappropriately high doses (37% higher on average) compared to the Cockcroft-Gault equation used in FDA dosing guidelines 5, 6

• Do not start at high doses (>300 mg/day) in elderly patients, even with normal renal function, due to increased risk of adverse events 3

• Do not exceed 12-hour intervals between doses, as this reduces efficacy 1

• Do not abruptly discontinue—taper gradually over minimum 1 week if stopping 1

• Do not assume "normal" serum creatinine means normal renal function in elderly patients with reduced muscle mass—always calculate creatinine clearance 7, 5

Monitoring Recommendations

• Assess for adverse effects at each dose escalation, particularly dizziness (occurs in elderly patients frequently) and sedation 2
• Re-evaluate renal function periodically, as age-related decline may occur 7
• Consider dose reduction if intolerable side effects develop rather than discontinuing therapy 4