From the FDA Drug Label
Apparent oral clearance of gabapentin was directly proportional to creatinine clearance. 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). Mean plasma clearance (CL/F) decreased from approximately 190 mL/min to 20 mL/min
Gabapentin and Kidney Function: The pharmacokinetics of gabapentin are affected by kidney function.
- Key Points:
- Apparent oral clearance of gabapentin is directly proportional to creatinine clearance.
- Gabapentin half-life increases with decreasing creatinine clearance.
- Renal clearance of gabapentin decreases with decreasing creatinine clearance.
- Clinical Decision: Gabapentin dosage should be adjusted in patients with renal impairment to avoid toxicity, as the drug's clearance is decreased in these patients 1. It is essential to monitor kidney function and adjust the dosage accordingly to ensure safe and effective use of gabapentin.
From the Research
Gabapentin requires dose adjustment in patients with reduced kidney function to minimize the risk of adverse events, particularly in older adults with chronic kidney disease (CKD) 2.
Key Considerations
- For patients with kidney impairment, dosing should be reduced based on creatinine clearance levels.
- Those with normal kidney function (creatinine clearance >60 mL/min) can take standard doses of 300-1200 mg three times daily.
- For moderate impairment (creatinine clearance 30-59 mL/min), reduce to 200-700 mg twice daily.
- For severe impairment (creatinine clearance 15-29 mL/min), limit to 200-700 mg once daily.
- Patients on hemodialysis should receive 100-300 mg after each dialysis session.
Rationale
Gabapentin is eliminated almost entirely by the kidneys without metabolism, which is why dose adjustment is necessary 3. Without proper adjustment, the drug can accumulate in the body, potentially causing excessive sedation, dizziness, and confusion.
Monitoring and Precautions
- Kidney function should be monitored regularly while taking gabapentin, especially in elderly patients or those with diabetes or hypertension.
- Any new symptoms like unusual fatigue, swelling, or changes in urination should prompt medical evaluation.
- Patients should never adjust gabapentin doses themselves without consulting their healthcare provider.
Evidence-Based Recommendations
The most recent and highest quality study 2 suggests that starting a gabapentinoid at a higher versus a lower dose is associated with a slightly higher risk of a hospital visit with encephalopathy, a fall, or a fracture or hospitalization with respiratory depression. Therefore, it is crucial to balance the benefits of using a higher-dose gabapentinoid against these risks.