Drug interactions
Quinine + Warfarin
Severity: Moderate
Quinine 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
Quinine may enhance the anticoagulant effect of warfarin and increase INR, with a higher risk of bleeding. The effect has been described in case reports and is variable.
What this interaction means in plain words
Quinine 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.
Quinine belongs to Anti Parasitic; Warfarin belongs to Cardiovascular.
Why it happens
Quinine may impair hepatic synthesis of vitamin K-dependent clotting factors and possibly affect warfarin metabolism.
What to do
Check INR within a few days of starting or stopping quinine and adjust the warfarin dose accordingly. Counsel the patient on signs of bleeding.
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 Quinine
- Arsenic trioxide + Quinine Contraindicated
- Dofetilide + Quinine Contraindicated
- Dronedarone + Quinine Contraindicated
- Ibutilide + Quinine Contraindicated
- Mefloquine + Quinine Contraindicated
- Nilotinib + Quinine Contraindicated
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 Quinine with Warfarin?
MediHelp rates the interaction as moderate. Quinine 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. Quinine may enhance the anticoagulant effect of warfarin and increase INR, with a higher risk of bleeding. The effect has been described in case reports and is variable.
How serious is the interaction between Quinine 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: Check INR within a few days of starting or stopping quinine and adjust the warfarin dose accordingly. Counsel the patient on signs of bleeding.
What other medicines interact with Quinine?
MediHelp also lists interactions of Quinine with, for example, Arsenic trioxide, Dofetilide, Dronedarone. The full list is on the Quinine page.
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