Bupropion Dosing in Moderate Renal Impairment
For patients with moderate renal impairment, the bupropion dose should be reduced to approximately 50% of the normal dose due to decreased renal clearance of the drug and its metabolites. 1
Pharmacokinetic Considerations
- Bupropion is extensively metabolized in the liver to active metabolites, which are further metabolized and excreted by the kidneys 1
- In patients with renal impairment, bupropion and its metabolites may accumulate to a greater extent than in patients with normal renal function 1, 2
- Studies show that bupropion AUC is 126% higher, Cmax is 86% higher, and half-life is 140% longer in patients with renal impairment compared to those with normal renal function 2
Specific Dosing Recommendations
- For patients with moderate renal impairment (GFR 30-49 mL/min), reduce the total daily dose by one-half 3
- If using extended-release formulations, consider 150 mg once daily instead of twice daily 1
- For combination products like naltrexone-bupropion ER, the recommended dose in moderate to severe renal impairment is one tablet twice per day (half the standard maintenance dose) 3
- Monitor closely for adverse reactions that could indicate high bupropion or metabolite exposures 1
Special Considerations
- Bupropion should be avoided in end-stage renal disease 3
- In patients with both renal and hepatic impairment, more aggressive dose reductions may be necessary 1
- Elderly patients are more likely to have decreased renal function and may require dose adjustments even with mild renal impairment 1
Potential Adverse Effects with Renal Impairment
- Case reports describe neurological symptoms including tremor, ataxia, and mental status changes in elderly patients with renal impairment taking bupropion, even at standard doses 4
- Symptoms of toxicity may include agitation, delirium, speech disturbances, and motor abnormalities 4
- These symptoms typically improve within 36-48 hours of dose reduction or discontinuation 4
Monitoring Recommendations
- Assess renal function before initiating therapy and periodically during treatment 1
- Monitor for signs of toxicity including neurological symptoms, agitation, or changes in mental status 4
- Consider more frequent monitoring in elderly patients or those with fluctuating renal function 1
Unlike some other medications that require more aggressive dose adjustments in renal impairment, bupropion requires moderate adjustment. However, it's important to note that the FDA specifically recommends dose reduction for patients with any degree of renal impairment (GFR <90 mL/min) 1.