Drug interactions
Saquinavir + Warfarin
Severity: Moderate
Saquinavir and Warfarin: 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
Ritonavir-boosted saquinavir may change warfarin exposure through effects on several CYP enzymes. The direction of the effect is unpredictable, and either INR elevation with bleeding or reduced anticoagulation can occur.
What this interaction means in plain words
Saquinavir and Warfarin 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
Saquinavir/ritonavir inhibits CYP3A4 and may also induce other enzymes, altering warfarin metabolism.
What to do
Monitor INR closely when saquinavir is started or stopped. Adjust the warfarin dose based on INR results.
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 Warfarin
- Defibrotide + Warfarin Contraindicated
- Ketorolac + Warfarin Contraindicated
- Abciximab + Warfarin Major
- Acetylsalicylic acid + Warfarin Major
- Adagrasib + Warfarin Major
- Amiodarone + Warfarin Major
Frequently asked questions
Can I take Saquinavir with Warfarin?
MediHelp rates the interaction as moderate. Saquinavir and Warfarin 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. Ritonavir-boosted saquinavir may change warfarin exposure through effects on several CYP enzymes. The direction of the effect is unpredictable, and either INR elevation with bleeding or reduced anticoagulation can occur.
How serious is the interaction between Saquinavir and Warfarin?
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 closely when saquinavir is started or stopped. Adjust the warfarin dose based on INR results.
What other medicines interact with Warfarin?
MediHelp also lists interactions of Warfarin with, for example, Defibrotide, Ketorolac, Abciximab. The full list is on the Warfarin page.
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