Drug interactions
Azathioprine + Sulfamethoxazole
Severity: Moderate
Azathioprine and Sulfamethoxazole: moderate interaction.
Last updated
For healthcare professionals — reference only. This page is a brief summary, not medical advice and not a substitute for official labeling or clinical judgement. Always verify before prescribing or dispensing.
Summary
Both azathioprine and sulfamethoxazole (usually given with trimethoprim) can suppress bone marrow. Combined use has been associated with leukopenia and other cytopenias, sometimes severe.
What this interaction means in plain words
Azathioprine and Sulfamethoxazole can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken.
Why it happens
Additive myelosuppression, with trimethoprim's antifolate effect likely contributing.
What to do
Monitor full blood counts regularly, especially in the first weeks of co-therapy. Reduce the azathioprine dose or stop the antibiotic if leukopenia develops.
What to ask your pharmacist
- Should I take them at different times of day?
- Does the dose of either medicine need to change?
- Is there anything I should avoid, such as alcohol or certain foods, while on both?
Pro+ members
Unlock the full page
Create an account and start a Pro+ trial to unlock the full management advice for Azathioprine and Sulfamethoxazole, the additional notes, the evidence detail and the whole-prescription interaction checker.
- Full clinical management advice
- Additional notes
- Evidence detail
- Interaction checker for a whole prescription
Try Pro+ free for 7 days on the web. No card needed.
Other interactions of Azathioprine
- Adenovirus types 4 and 7 live + Azathioprine Contraindicated
- Azathioprine + Bcg vaccine live Contraindicated
- Azathioprine + Febuxostat Contraindicated
- Azathioprine + Influenza virus vaccine quadrivalent intranasal Contraindicated
- Azathioprine + Measles mumps and rubella vaccine Contraindicated
- Azathioprine + Measles mumps and rubella vaccine live Contraindicated
Frequently asked questions
Can I take Azathioprine with Sulfamethoxazole?
MediHelp rates the interaction as moderate. Azathioprine and Sulfamethoxazole can affect each other. The combination is often manageable, but it may need a change of dose, a change of timing, or extra checks while both are taken. Both azathioprine and sulfamethoxazole (usually given with trimethoprim) can suppress bone marrow. Combined use has been associated with leukopenia and other cytopenias, sometimes severe.
How serious is the interaction between Azathioprine and Sulfamethoxazole?
MediHelp rates it moderate, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Monitor full blood counts regularly, especially in the first weeks of co-therapy. Reduce the azathioprine dose or stop the antibiotic if leukopenia develops.
What other medicines interact with Azathioprine?
MediHelp also lists interactions of Azathioprine with, for example, Adenovirus types 4 and 7 live, Bcg vaccine live, Febuxostat. The full list is on the Azathioprine page.
Full monographs, dosing and an interaction checker in the MediHelp app
Open the complete reference, check multi-drug interactions and use dosing tools in the MediHelp app.
