From the FDA Drug Label
Adult Patients with Renal Impairment Subjects (N=60) with renal impairment (mean creatinine clearance ranging from 13 to 114 mL/min) were administered single 400 mg oral doses of gabapentin. The mean gabapentin half-life ranged from about 6. 5 hours (patients with creatinine clearance >60 mL/min) to 52 hours (creatinine clearance <30 mL/min) and gabapentin renal clearance from about 90 mL/min (>60 mL/min group) to about 10 mL/min (<30 mL/min).
Gabapentin is okay until an eGFR of 30 mL/min, below which the half-life increases significantly and the renal clearance decreases substantially 1.
- Key points: + The mean gabapentin half-life increases as creatinine clearance decreases. + Gabapentin renal clearance decreases as creatinine clearance decreases. + Patients with creatinine clearance <30 mL/min have a significantly longer half-life and lower renal clearance.
From the Research
Gabapentin is generally considered safe to use in patients with an eGFR above 30 mL/min, but dose adjustments are necessary as eGFR decreases, with more significant reductions needed for eGFR below 15 mL/min. When considering the use of gabapentin in patients with reduced kidney function, it's crucial to understand that gabapentin is primarily eliminated unchanged through the kidneys. As a result, dose reduction is necessary as kidney function declines to prevent accumulation and increased side effects such as dizziness, somnolence, and confusion 2. For patients with an eGFR above 60 mL/min, standard dosing can be used, but when eGFR is between 30-59 mL/min, the dose should be reduced to 200-700 mg twice daily 3. For eGFR between 15-29 mL/min, the recommendation is 200-700 mg once daily, and in severe kidney impairment with eGFR less than 15 mL/min, gabapentin should be given at 100-300 mg once daily 4. Regular monitoring of kidney function is important for patients on gabapentin, especially those with known kidney disease or the elderly, to ensure safe use and minimize the risk of adverse events 5, 6. Key considerations include:
- Dose adjustments based on eGFR levels
- Monitoring for signs of gabapentin accumulation or toxicity
- Awareness of potential interactions with other medications
- Consideration of alternative treatments when eGFR is significantly impaired. Given the most recent evidence from 2, which highlights the importance of appropriate dosing in patients with decreased kidney function to minimize adverse effects, the use of gabapentin in patients with an eGFR below 30 mL/min requires careful consideration and dose adjustment to prevent adverse outcomes.