Drug interactions
Azathioprine + Phenindione
Severity: Moderate
Azathioprine and Phenindione: 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
Azathioprine has been reported to reduce the anticoagulant effect of coumarin-type anticoagulants such as warfarin, and phenindione may behave similarly. A weaker anticoagulant effect could leave the patient at risk of thrombosis.
What this interaction means in plain words
Azathioprine and Phenindione 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
The mechanism is not established; the effect is extrapolated from reports of reduced warfarin response with azathioprine.
What to do
Monitor INR more often when azathioprine is started or stopped, and adjust the phenindione dose to maintain the target range.
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?
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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 Phenindione?
MediHelp rates the interaction as moderate. Azathioprine and Phenindione 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. Azathioprine has been reported to reduce the anticoagulant effect of coumarin-type anticoagulants such as warfarin, and phenindione may behave similarly. A weaker anticoagulant effect could leave the patient at risk of thrombosis.
How serious is the interaction between Azathioprine and Phenindione?
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 INR more often when azathioprine is started or stopped, and adjust the phenindione dose to maintain the target range.
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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