Drug interactions
Azathioprine + Smallpox vaccine live
Severity: Contraindicated
Azathioprine and Smallpox vaccine live: contraindicated interaction.
Last updated Sources: EMA SmPC
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
Live vaccinia virus can cause progressive vaccinia and other serious complications in immunosuppressed patients. Azathioprine raises this risk substantially.
What this interaction means in plain words
Azathioprine and Smallpox vaccine live 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.
Why it happens
Azathioprine impairs cellular immunity, allowing uncontrolled replication of live vaccinia virus.
What to do
Avoid replicating live smallpox vaccine in patients on azathioprine. Use a non-replicating vaccine if one is available and seek specialist advice.
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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References
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 Smallpox vaccine live?
MediHelp rates the interaction as contraindicated. Azathioprine and Smallpox vaccine live 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. Live vaccinia virus can cause progressive vaccinia and other serious complications in immunosuppressed patients. Azathioprine raises this risk substantially.
How serious is the interaction between Azathioprine and Smallpox vaccine live?
MediHelp rates it contraindicated, on a four-level scale (minor, moderate, major, contraindicated) based on published labels and references. What to do, in brief: Avoid replicating live smallpox vaccine in patients on azathioprine. Use a non-replicating vaccine if one is available and seek specialist advice.
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.
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