Phenindione
Phenindione is an oral anticoagulant medication that works by inhibiting vitamin K-dependent clotting factors in the blood. It is primarily used to prevent and treat blood clots in conditions such as deep vein thrombosis, pulmonary embolism, and atrial fibrillation, though it has largely been replaced by safer alternatives like warfarin.
Phenindione is a vitamin K antagonist anticoagulant used to prevent and treat harmful blood clots.
Key facts at a glance
- ATC
- B01AA02
- RxNorm
- 8130
- Generic
- Phenindione
- Class
- atc-b01
- Brands
- —
- Availability
- rx
- Lactation
- unknown
- Routes
- oral
- Forms
- tablet
- Regions
- US, EU, CN, JP
- Monitoring
- —
This page is for informational purposes only.
Do not use this information to diagnose yourself or to replace a physician's advice. Always consult a qualified healthcare provider before starting, stopping, or changing any medication. If you believe you are experiencing a medical emergency, call your local emergency number immediately.
Prevention and treatment of venous thromboembolism (deep vein thrombosis and pulmonary embolism), prevention of stroke in atrial fibrillation, and prevention of clotting after heart valve replacement surgery.
Phenindione inhibits vitamin K epoxide reductase, blocking the synthesis of vitamin K-dependent clotting factors (II, VII, IX, and X) and anticoagulant proteins C and S, thereby reducing the blood's ability to clot.
Requires regular INR monitoring to ensure therapeutic effect and prevent bleeding complications. Has been largely superseded by warfarin due to its more favorable side effect profile. May cause orange-red discoloration of body fluids and rare but serious blood dyscrasias.
Official drug label
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This information is for educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment.
This content is for general informational and educational purposes only and is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the guidance of a qualified healthcare provider with any questions you have about a medical condition, and never disregard professional medical advice or delay seeking it because of something you read here.
If you think you may have a medical emergency, call your local emergency number or go to the nearest emergency department immediately.
Medically reviewed by WellAlly Editorial Team Last reviewed August 25, 2026. · Read our editorial policy