Gabapentin Clearance with Dialysis
Gabapentin is effectively removed by hemodialysis with a clearance of approximately 142 mL/min (about 93% of creatinine clearance), reducing its elimination half-life from 132 hours in anuric patients to approximately 3.8-4 hours during dialysis sessions. 1, 2
Pharmacokinetics in Dialysis Patients
Hemodialysis Clearance
- Hemodialysis removes approximately 35% of a gabapentin dose during a single 4-hour session, with mean dialysis clearance of 142 mL/min 2
- The elimination half-life drops dramatically from 132 hours on non-dialysis days to 3.8-4 hours during active hemodialysis 1, 2
- Post-dialysis redistribution occurs: plasma gabapentin concentrations increase approximately 30% during the first 2 hours after hemodialysis ends due to drug redistribution from tissues back into plasma 2
Peritoneal Dialysis Clearance
- Continuous automated peritoneal dialysis provides significant but slower gabapentin clearance compared to hemodialysis 3
- With 2-liter exchanges every 2 hours, the apparent elimination half-life is approximately 41 hours—substantially shorter than 132 hours without dialysis, but much longer than hemodialysis 3
- Gabapentin clearance by peritoneal dialysis is estimated at 94% of urea clearance, making it an effective but slower method for treating gabapentin toxicity 3
Dosing Recommendations for Hemodialysis Patients
Loading and Maintenance Dosing
- Initial loading dose: 300-400 mg gabapentin for patients with end-stage renal disease on hemodialysis 2
- Maintenance dosing: 200-300 mg after every 4 hours of hemodialysis to maintain therapeutic plasma concentrations 2
Clinical Guideline Dosing (for Uremic Pruritus)
- The British Association of Dermatologists recommends 100-300 mg post-dialysis, three times per week (after each dialysis session) 4, 5
- A multicenter trial demonstrated good efficacy with just 100 mg post-dialysis three times weekly, achieving >50% reduction in symptom scores 4, 5
- Studies have also shown efficacy with 400 mg twice weekly after hemodialysis sessions 4, 5
- These doses are substantially lower than those used in patients with normal renal function, reflecting the dramatic reduction in clearance 4
Critical Timing Considerations
Always administer gabapentin after hemodialysis sessions, not before, to avoid premature drug removal during dialysis and to facilitate directly observed therapy 4, 6
Toxicity Risk and Monitoring
High-Risk Population
- Approximately 19% of US dialysis patients receive gabapentin, with increased risk of altered mental status, falls, and fractures 7
- The elimination half-life of 132 hours in anuric patients creates substantial accumulation risk with standard dosing 1, 7
Common Adverse Effects
- Dizziness and drowsiness are the most frequent side effects, even at reduced doses 4, 5, 8
- Drug monitoring should be used to avoid unintended overdose in dialysis patients, as gabapentin has a narrow therapeutic window in this population 7
Renal Function-Based Dosing Algorithm
For patients with creatinine clearance <30 mL/min or on hemodialysis:
- Increase dosing interval rather than decreasing dose to maintain adequate peak concentrations while avoiding accumulation 4
- Gabapentin oral clearance is directly proportional to creatinine clearance, with approximately 1.6-fold decrease in clearance for every 2-fold decrease in creatinine clearance 8
- The FDA label confirms that gabapentin renal clearance decreases from approximately 190 mL/min (normal function) to about 10 mL/min (CrCl <30 mL/min) 1