Can I take 1.5mg and Pentasa together?
Drug interaction guide
Originally published 14 Mar 2026
Meets Patient’s editorial guidelines
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Taking these two medicines together can increase the risk of serious side effects, particularly a drop in your white blood cell count. This can make you much more likely to pick up infections. It can also affect your bone marrow's ability to produce new blood cells.
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Why this happens
Both medicines can suppress the bone marrow. Pentasa (mesalazine) can also interfere with how the body breaks down azathioprine, leading to higher levels of azathioprine in your blood than intended.
What you should do
Back to contentsYou must speak to your doctor before taking these together. If your doctor prescribes both, you will need very regular blood tests to monitor your blood cell counts and liver function. Seek medical help immediately if you develop a fever, sore throat, unexplained bruising, or feel generally unwell.
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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.
14 Mar 2026 | Originally published
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