Does Sulfamethoxazole And Trimethoprim Interact with Leucovorin Calcium?
Sulfamethoxazole And Trimethoprim and Leucovorin Calcium have a contraindicated drug interaction according to U.S. FDA drug labeling data. Avoid concomitant use. Leucovorin decreases effectiveness of trimethoprim-sulfamethoxazole, associated with increased treatment failure and mortality in HIV patients with Pneumocystis jirovecii pneumonia. The mechanism involves leucovorin reduces the effectiveness of trimethoprim-sulfamethoxazole. 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
- Sulfamethoxazole And Trimethoprim Class
- Sulfonamide Antimicrobial
- Management
- Do not take together
- Data Source
- U.S. FDA via OpenFDA
How This Interaction Works
The interaction between Sulfamethoxazole And Trimethoprim and Leucovorin Calcium occurs because leucovorin reduces the effectiveness of trimethoprim-sulfamethoxazole. Clinically, this means avoid concomitant use. leucovorin decreases effectiveness of trimethoprim-sulfamethoxazole, associated with increased treatment failure and mortality in hiv patients with pneumocystis jirovecii pneumonia. Because of the severity of this interaction, these medications are contraindicated — meaning they should not be taken together under any circumstances. If you are currently taking both, contact your healthcare provider immediately to discuss alternatives.
What To Tell Your Doctor or Pharmacist
If you are taking Sulfamethoxazole And Trimethoprim and your doctor is considering prescribing Leucovorin Calcium (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