Can I take Azathioprine and Tadalafil together?
Drug interaction guide
Originally published 12 May 2026
Meets Patient’s editorial guidelines
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There is no known direct interaction between azathioprine and tadalafil. It is generally considered safe to take these two medications together.
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Why this happens
Azathioprine is an immunosuppressant processed primarily by the thiopurine methyltransferase (TPMT) enzyme system. Tadalafil is a PDE5 inhibitor used for erectile dysfunction or pulmonary hypertension, processed mainly by the CYP3A4 enzyme in the liver. Because they use different pathways in the body and have different targets, they do not interfere with each other's effectiveness or safety.
What you should do
Back to contentsYou can take these medicines together as prescribed. However, azathioprine can sometimes affect your liver or blood counts, so ensure you are attending your regular blood test appointments. If you experience any unusual side effects like extreme dizziness or signs of an infection, contact your doctor.
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Using other medicines
Back to contentsTaking multiple medicines? Our Medicines Interaction Checker helps you check whether your prescriptions, over-the-counter medicines, and supplements are safe to take together. Simply search for your medicines to see potential interactions and what to do about them.
Disclaimer
This information is for general educational purposes only and should not be relied upon as a substitute for professional medical advice. Always consult your GP, pharmacist, or another qualified healthcare professional before making decisions about your medications. Individual circumstances may vary, and only a healthcare professional who knows your medical history can provide personalised guidance.
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Article history
The information on this page is written and peer reviewed by qualified clinicians.
12 May 2026 | Originally published

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