Cotrimoxazole has 19 known drug interactions based on U.S. FDA drug labeling data. Of these, 2 are contraindicated combinations that should be avoided entirely. 4 are classified as major interactions requiring close medical supervision. Notable interactions include combinations with Methylergonovine, Methylergonovine Maleate, Tacrolimus. Patients taking Cotrimoxazole should inform their healthcare provider of all current medications — including over-the-counter drugs and supplements — to avoid potentially harmful combinations. Data sourced from OpenFDA and the NIH National Library of Medicine.
- Total
- 19
- Contraindicated
- 2
- Major
- 4
- Moderate
- 5
Contraindicated (2)
- Cotrimoxazole + Methylergonovine— Moderate CYP 3A4 inhibitor; should not be co-administered with methylergonovine.
- Cotrimoxazole + Methylergonovine Maleate— Moderate CYP 3A4 inhibitor; should not be co-administered with methylergonovine to avoid vasospasm risk.
Major (4)
- Cotrimoxazole + Tacrolimus— Mild or Moderate CYP3A Inhibitors: Clotrimazole, antibiotics (e.g., erythromycin, fluconazole), calcium channel blockers…
- Cotrimoxazole + Tacrolimus Extended-Release Capsules— Mild or Moderate CYP3A Inhibitors: Clotrimazole, antibiotics (e.g., verapamil, diltiazem, nifedipine, nicardipine), amio…
- Cotrimoxazole + Warfarin— CYP2C9 inhibitor that increases warfarin effect and INR; requires close INR monitoring
- Cotrimoxazole + Warfarin Sodium— CYP2C9 inhibitor that increases warfarin effect and INR; requires closer INR monitoring.
Moderate (5)
- Cotrimoxazole + Amphotericin B— Imidazoles may induce fungal resistance to amphotericin B. Combination therapy should be administered with caution, espe…
- Cotrimoxazole + Amphotericin B Liposome— In vitro and in vivo animal studies suggest imidazoles may induce fungal resistance to amphotericin B. Combination thera…
- Cotrimoxazole + Diazepam— CYP3A4 inhibitor that decreases diazepam elimination, potentially increasing adverse reactions.
- Cotrimoxazole + Dihydroergotamine Mesylate— Administer moderate CYP3A4 inhibitors (e.g., saquinavir, nefazodone, fluconazole, grapefruit juice, fluoxetine, fluvoxam…
- Cotrimoxazole + Rapamycin— Weak/moderate CYP3A4/P-gp inhibitor that may increase sirolimus concentrations. Monitor and adjust dosage as needed.