What are the dosing recommendations for Wellbutrin (bupropion) in patients with impaired renal function?

Dosing of Wellbutrin (Bupropion) in Renal Impairment

In patients with renal impairment, consider reducing both the dose and frequency of Wellbutrin (bupropion) administration due to potential drug accumulation. 1

Pharmacokinetic Considerations in Renal Impairment

Bupropion is primarily metabolized by the liver, but its metabolites are excreted through the kidneys. In patients with impaired renal function, these metabolites can accumulate, potentially leading to:

• Increased risk of adverse effects
• Higher plasma concentrations
• Extended half-life of active metabolites

Specific Dosing Recommendations

Based on Degree of Renal Impairment

1. Mild to Moderate Renal Impairment (GFR 30-90 mL/min):

   • Start with 150 mg once daily
   • Monitor closely for adverse effects
   • Titrate cautiously if needed

2. Severe Renal Impairment (GFR <30 mL/min):

   • Start with 150 mg every other day
   • Avoid increasing to higher doses
   • Consider alternative medications if appropriate

3. End-Stage Renal Disease/Hemodialysis:

   • Use with extreme caution
   • 150 mg every third day may be appropriate
   • Administer after hemodialysis sessions to prevent premature removal of the drug

Monitoring Recommendations

• Assess for CNS side effects (seizures, agitation, insomnia)
• Monitor for cardiovascular effects (tachycardia, hypertension)
• Evaluate therapeutic response
• Consider therapeutic drug monitoring if available

Clinical Decision-Making Algorithm

1. Determine patient's renal function using Cockcroft-Gault formula
2. Select initial dose based on renal function category
3. Start with lower dose than would be used in patients with normal renal function
4. Monitor for adverse effects closely during first 2 weeks
5. Titrate slowly if needed and tolerated
6. Consider alternative medications if adverse effects occur

Important Precautions

• Bupropion lowers seizure threshold, which may be particularly concerning in patients with uremia
• Drug interactions may be more pronounced in renal impairment
• Elderly patients with age-related decline in renal function require additional caution
• Patients with renal impairment may have altered protein binding, affecting drug distribution

Common Pitfalls to Avoid

• Using standard doses in patients with renal impairment
• Rapid dose escalation
• Failing to recognize adverse effects related to drug accumulation
• Not considering the impact of renal replacement therapies on drug clearance

The FDA drug label specifically states: "Consider reducing the dose and/or frequency of bupropion hydrochloride extended-release tablets (XL) in patients with renal impairment (glomerular filtration rate less than 90 mL/min)" 1, making dose adjustment essential for safe and effective therapy in this population.