Does Sulfamethoxazole Interact with Rifabutin?
Sulfamethoxazole and Rifabutin have a contraindicated drug interaction according to U.S. FDA drug labeling data. Voriconazole 400 mg twice a day for 7 days (maintenance dose) 300 mg once a day for 7 days Healthy male subjects (12) ↑ AUC by 331%, ↑ C max by 195% ↑ AUC by ~100%, ↑ C max by ~100% g CONTRAINDICATED ANTI-PCP (Pneumocystis carinii pneumonia) Dapsone 50 mg once a day 300 mg once a day HIV infected patients (16) ND ↓ AUC by 27 -40% Sulfamethoxazole-Trimethoprim 800/160 mg 300 mg once a day HIV infected patients (12) ↓ AUC by 15-20% ANTI-MAC (Mycobacterium avium intracellulare complex) Azithromycin 500 mg once a day for 1 day, then 250 mg once a day for 9 days 300 mg once a day Healthy subjects (6) Clarithromycin 500 mg twice a day 300 mg once a day HIV infected patients (12) ↑ AUC by 75% ↓ AUC by 50% Monitor for rifabutin associated adverse events. Patients taking both medications should consult their healthcare provider before starting, stopping, or changing the dosage of either drug. This information is based on official FDA drug labeling sourced from OpenFDA and the NIH National Library of Medicine.
- Severity
- Contraindicated
- Rifabutin Class
- Rifamycin Antimycobacterial
- Management
- Do not take together
- Data Source
- U.S. FDA via OpenFDA
What To Tell Your Doctor or Pharmacist
If you are taking Sulfamethoxazole and your doctor is considering prescribing Rifabutin (or vice versa), make sure to:
- Inform your doctor and pharmacist of all current medications, including over-the-counter drugs and supplements
- Ask whether the benefits of combining these medications outweigh the risks for your specific situation
- Ask what symptoms to watch for that would indicate the interaction is causing problems
- Ask about alternative medications that do not interact with your current regimen
- Ask how frequently you should be monitored while these are co-prescribed
- Never stop or change either medication without first consulting your healthcare provider