Gabapentin Dosing in Hemodialysis
For patients undergoing hemodialysis, gabapentin should be dosed at 100-300 mg once daily with a supplemental post-hemodialysis dose of 125-350 mg after each 4-hour hemodialysis session. 1
Pharmacokinetics in Renal Impairment
- Gabapentin is exclusively eliminated by renal excretion and is not bound to plasma proteins, making dosage adjustment essential in patients with impaired renal function 2
- In anuric patients on hemodialysis, gabapentin has an elimination half-life of approximately 132 hours on non-dialysis days, compared to 5-9 hours in patients with normal renal function 2, 3
- During hemodialysis, the elimination half-life decreases to approximately 4 hours, with hemodialysis clearing about 35% of the drug 2
Dosing Recommendations Based on Renal Function
For Patients with Creatinine Clearance <15 mL/min:
- 100-300 mg once daily 1
- Reduce daily dose in proportion to creatinine clearance (e.g., patients with creatinine clearance of 7.5 mL/min should receive one-half the daily dose that patients with creatinine clearance of 15 mL/min receive) 1
For Hemodialysis Patients:
- Maintenance dose: 100-300 mg once daily 1
- Supplemental post-hemodialysis dose: 125-350 mg after each 4-hour hemodialysis session 1
- Administer gabapentin after hemodialysis to avoid premature removal of the drug 2
Monitoring and Safety Considerations
- Plasma gabapentin concentrations increase approximately 30% during the first 2 hours after hemodialysis due to drug redistribution in the body 2
- Gabapentin toxicity in patients with renal impairment can manifest as altered mental status, confusion, hallucinations, myoclonus, and even reversible hearing loss 4
- Regular monitoring of gabapentin levels is recommended to avoid unintended overdose, as approximately 19% of dialysis patients receive gabapentin, with associated risks of altered mental status, falls, and fractures 3
Alternative Dialysis Modalities
- Peritoneal dialysis provides significant but slower clearance of gabapentin compared to hemodialysis 5
- With 2-L exchanges every 2 hours in continuous automated cycling peritoneal dialysis, the elimination half-life is approximately 41.33 hours (vs. 132 hours without dialysis) 5
- Gabapentin clearance by peritoneal dialysis is estimated at 94% of urea clearance 5
Practical Administration Tips
- Gabapentin can be administered orally with or without food 1
- For elderly patients, who are more likely to have decreased renal function, dose should be adjusted based on creatinine clearance values 1
- If gabapentin dose needs to be reduced, discontinued, or substituted, this should be done gradually over a minimum of 1 week to avoid withdrawal symptoms 1
Remember that inappropriate dosing of gabapentin in hemodialysis patients can lead to serious adverse effects including neurotoxicity, which may necessitate extensive diagnostic workups if not recognized early as medication-related 3.