What is the recommended dosing of bupropion for a patient with a Creatinine Clearance (CrCL) of 59 and a Glomerular Filtration Rate (GFR) of 62?

Bupropion Dosing in Renal Impairment

For a patient with CrCl of 59 mL/min, GFR of 62 mL/min, AST 48, and ALT 68, the recommended dose of bupropion is 150 mg once daily, with careful monitoring for adverse effects. 1

Renal Considerations for Bupropion

• Bupropion is extensively metabolized in the liver to active metabolites, which are further metabolized and excreted by the kidneys 1
• For patients with glomerular filtration rate <90 mL/min (including your patient with CrCl 59 mL/min), a reduced dose and/or dosing frequency of bupropion is recommended 1
• The risk of adverse reactions may be greater in patients with impaired renal function due to potential accumulation of bupropion and its metabolites 1

Specific Dosing Recommendations

• For moderate renal impairment (CrCl 30-59 mL/min), which applies to your patient:
  • Start with 150 mg once daily (not twice daily as would be used in normal renal function) 1, 2
  • Monitor closely for adverse reactions that could indicate high bupropion or metabolite exposures 1
  • Avoid increasing to 150 mg twice daily as this has been associated with increased risk of adverse effects in patients with renal impairment 2, 3

Pharmacokinetic Considerations

• Studies have shown that in renal impairment, bupropion clearance (CL/F) is 63% lower and half-life is 140% longer compared to individuals with normal renal function 2
• The hydroxybupropion:bupropion AUC ratio is decreased by 66% in renally impaired subjects, indicating altered metabolism 2
• A single-dose study in hemodialysis patients suggested that 150 mg every 3 days would be appropriate for severe renal impairment, indicating the need for significant dose reduction even in moderate impairment 4

Monitoring Recommendations

• Monitor for signs of bupropion toxicity including agitation, insomnia, seizures, and dystonic reactions 1, 3
• Assess renal function periodically during treatment as further decline may necessitate additional dose adjustments 1
• Be vigilant for drug interactions that might further impair bupropion clearance or increase risk of adverse effects 1

Hepatic Considerations

• Your patient has mildly elevated liver enzymes (AST 48, ALT 68)
• While these values don't indicate severe hepatic impairment, they warrant monitoring as bupropion is extensively metabolized in the liver 1
• If liver function deteriorates, further dose adjustment may be necessary 1

Common Pitfalls to Avoid

• Avoid starting at the standard dose of 150 mg twice daily, as this has been associated with increased adverse effects in patients with renal impairment 2, 3
• Do not increase the dose rapidly; allow sufficient time between dose adjustments to assess tolerability 1, 3
• Remember that bupropion and its metabolites may accumulate in renal impairment, potentially leading to delayed toxicity 1, 2