Gabapentin Dosing in Kidney Disease
Gabapentin requires mandatory dose reduction in patients with impaired renal function based on creatinine clearance, as the drug is eliminated unchanged by the kidneys and failure to adjust dosing causes preventable toxicity. 1, 2
Calculate Creatinine Clearance First
Always calculate creatinine clearance using the Cockcroft-Gault equation before prescribing gabapentin—never rely on serum creatinine alone, especially in elderly patients or those with reduced muscle mass, as this significantly underestimates renal impairment and leads directly to toxicity. 2, 3, 4
Gabapentin clearance is directly proportional to creatinine clearance, with approximately a 1.6-fold decrease in drug clearance for every 2-fold decrease in CrCl. 5, 6
The elimination half-life increases from 5-9 hours in normal renal function to 132 hours in dialysis patients, making accurate dosing critical. 7
FDA-Approved Dosing by Renal Function
Use the following FDA-approved dosing table for patients ≥12 years old: 1
CrCl ≥60 mL/min:
- Total daily dose: 900-3600 mg/day
- Dosing: 300-1200 mg three times daily (TID)
- No adjustment needed 1
CrCl 30-59 mL/min (Moderate Impairment):
- Total daily dose: 400-1400 mg/day
- Dosing: 200-700 mg twice daily (BID)
- Start at 100-300 mg at bedtime or TID, increase by 100-300 mg every 1-7 days as tolerated 8, 3, 1
- This represents at least a 50% dose reduction from normal dosing 2, 3
CrCl 15-29 mL/min (Severe Impairment):
- Total daily dose: 200-700 mg/day
- Dosing: 200-700 mg once daily (QD)
- Maximum time between doses should not exceed 12 hours 1
CrCl <15 mL/min (End-Stage Renal Disease):
- Total daily dose: 100-300 mg/day
- Dosing: 100-300 mg once daily 1
- For patients with CrCl <15 mL/min, reduce daily dose in proportion to creatinine clearance (e.g., CrCl of 7.5 mL/min receives half the dose of CrCl 15 mL/min) 1
Hemodialysis Patients:
- Give maintenance doses based on CrCl as above, PLUS a supplemental post-hemodialysis dose after each 4-hour dialysis session 1
- Supplemental doses: 125-350 mg depending on the maintenance regimen 1
- Gabapentin is effectively removed by hemodialysis, necessitating post-dialysis supplementation 6, 7
Critical Monitoring and Pitfalls
Monitor closely for dose-dependent adverse effects during titration, particularly dizziness, sedation, confusion, and altered mental status—these are the most common signs of gabapentin toxicity in renal impairment. 3, 7, 9
Patients at highest risk for gabapentin-related adverse events include those with older age, history of seizures, or concomitant antipsychotic use—exercise extra caution in these populations. 9
Temporarily discontinue gabapentin during acute illness that increases risk of acute kidney injury in patients with baseline CrCl <60 mL/min. 3
Inappropriate dosing occurs in 45% of hospitalized CKD patients receiving gabapentin, and adverse events are associated with significantly longer hospital stays (8.5 vs 5.3 days). 9
Reassess renal function periodically, as changes in kidney function require immediate dose adjustment. 2, 3
Titration Strategy
Start with the lowest recommended dose for the patient's CrCl category 8, 3, 1
Increase gradually by 100-300 mg every 1-7 days as tolerated, monitoring for sedation and dizziness 8, 3
The maximum time interval between doses should not exceed 12 hours, even in severe renal impairment 1
When discontinuing or reducing gabapentin, taper gradually over a minimum of 1 week to avoid withdrawal symptoms 1
Special Populations
Elderly patients require particularly careful dose selection based on creatinine clearance, as they are more likely to have decreased renal function that may not be apparent from serum creatinine alone. 4, 1
Pediatric patients <12 years old with renal impairment have not been adequately studied, and no specific dosing recommendations exist for this population 1
In patients with cardiovascular disease requiring palliative care, gabapentin is typically not recommended as a first-line agent due to risks of fluid retention, weight gain, and heart failure exacerbation 3