Drug interactions
Azathioprine + Mercaptopurine
Severity: Contraindicated
Azathioprine and Mercaptopurine: contraindicated 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
Azathioprine is converted in the body to mercaptopurine, so giving both drugs duplicates the same active thiopurine exposure. This raises the risk of profound myelosuppression, serious infection and hepatotoxicity.
What this interaction means in plain words
Azathioprine and Mercaptopurine are not normally used together. Taking them at the same time is expected to cause harm or make one of them unsafe, so a different medicine is usually chosen for one of the two.
Azathioprine belongs to Gastrointestinal Tract; Mercaptopurine belongs to Oncology.
Why it happens
Therapeutic duplication: azathioprine is a prodrug of mercaptopurine, so both generate the same cytotoxic thioguanine nucleotides.
What to do
Do not combine the two drugs; use only one thiopurine at a time. If switching, stop one before starting the other and monitor blood counts.
What to ask your pharmacist
- Is there an alternative to one of these two medicines for me?
- If both are essential, who is monitoring me and how often?
- Which symptoms mean I should stop and seek help straight away?
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Other interactions of Mercaptopurine
- Adenovirus types 4 and 7 live + Mercaptopurine Contraindicated
- Bcg vaccine live + Mercaptopurine Contraindicated
- Febuxostat + Mercaptopurine Contraindicated
- Influenza virus vaccine quadrivalent intranasal + Mercaptopurine Contraindicated
- Mercaptopurine + Smallpox vaccine live Contraindicated
- Adalimumab + Mercaptopurine Major
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 Mercaptopurine?
MediHelp rates the interaction as contraindicated. Azathioprine and Mercaptopurine are not normally used together. Taking them at the same time is expected to cause harm or make one of them unsafe, so a different medicine is usually chosen for one of the two. Azathioprine is converted in the body to mercaptopurine, so giving both drugs duplicates the same active thiopurine exposure. This raises the risk of profound myelosuppression, serious infection and hepatotoxicity.
How serious is the interaction between Azathioprine and Mercaptopurine?
MediHelp rates it contraindicated, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Do not combine the two drugs; use only one thiopurine at a time. If switching, stop one before starting the other and monitor blood counts.
What other medicines interact with Mercaptopurine?
MediHelp also lists interactions of Mercaptopurine with, for example, Adenovirus types 4 and 7 live, Bcg vaccine live, Febuxostat. The full list is on the Mercaptopurine page.
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