What is the recommended dose of gabapentin (Gabapentin) for a 91-year-old patient with impaired renal function?

Gabapentin Dosing for a 91-Year-Old with Impaired Renal Function

For a 91-year-old patient with impaired renal function, gabapentin should be started at 100 mg once daily with careful titration based on creatinine clearance, not exceeding 300 mg daily for severe renal impairment. 1

Dosing Considerations Based on Renal Function

Gabapentin requires significant dosage adjustment in elderly patients with impaired renal function as it is exclusively eliminated unchanged through the kidneys. The FDA-approved dosing recommendations are:

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

1

Special Considerations for Elderly Patients

The FDA label specifically states that "because elderly patients are more likely to have decreased renal function, care should be taken in dose selection, and dose should be adjusted based on creatinine clearance values in these patients." 1

For a 91-year-old patient:

1. Start at the lowest possible dose (100 mg once daily)
2. Assess creatinine clearance before initiating therapy
3. Titrate very slowly - increase by no more than 100 mg every 7 days
4. Monitor for adverse effects, particularly:
   • Dizziness
   • Somnolence
   • Ataxia
   • Confusion
   • Edema

Titration Protocol for Very Elderly with Renal Impairment

Based on creatinine clearance:

• CrCl 15-29 mL/min: Start with 100 mg once daily, maximum 200-700 mg once daily 1
• CrCl <15 mL/min: Start with 100 mg once daily, maximum 100-300 mg once daily 1

The Journal of the American Geriatrics Society recommends even more conservative dosing for elderly patients, noting that "treatment should be initiated with a low starting dose, such as gabapentin 100 to 200 mg/day" with "dose escalation from the starting dose should be incremental and implemented at intervals long enough to allow monitoring of effects." 2

Monitoring Requirements

1. Baseline renal function assessment (creatinine clearance)
2. Regular monitoring of renal function during treatment
3. Assessment of adverse effects at each follow-up
4. Evaluation of pain relief efficacy using a numerical pain scale

Potential Adverse Effects to Monitor

Elderly patients are particularly susceptible to:

• Somnolence and dizziness (most common)
• Mental clouding and confusion
• Ataxia
• Peripheral edema
• Weight gain
• Falls risk

A recent population-based cohort study found that higher initial doses of gabapentinoids in older adults with CKD were associated with a higher 30-day risk of hospital visits for encephalopathy, falls, fractures, or respiratory depression compared to lower initial doses 3.

Conclusion

When prescribing gabapentin for a 91-year-old patient with impaired renal function, start with 100 mg once daily, assess renal function regularly, and titrate slowly based on both efficacy and tolerability. The maximum dose should be determined by the patient's creatinine clearance, but generally should not exceed 300 mg daily in severe renal impairment.