phenindione

Phenindione is an anticoagulant medication belonging to the indanedione class. It functions by inhibiting vitamin K epoxide reductase, an enzyme crucial for the synthesis of vitamin K-dependent clotting factors in the liver. This inhibition leads to a decrease in the production of factors II, VII, IX, and X, thereby reducing the blood's ability to clot. Phenindione is used to prevent and treat thromboembolic disorders, such as deep vein thrombosis and pulmonary embolism, as well as to reduce the risk of stroke in patients with atrial fibrillation.

The administration of phenindione typically involves oral dosage. Its onset of action is gradual, with anticoagulant effects becoming apparent after 24-72 hours, and the full effect taking several days to achieve. Monitoring of the prothrombin time (PT) or the international normalized ratio (INR) is essential to guide dosage adjustments and ensure therapeutic efficacy while minimizing the risk of bleeding complications.

Common side effects associated with phenindione include gastrointestinal disturbances, skin rash, and hair loss. More serious adverse reactions, though less common, can include hematuria, hepatitis, and hypersensitivity reactions. Due to its potential for toxicity and the availability of newer, safer anticoagulants, phenindione is less commonly prescribed in many regions compared to warfarin or direct oral anticoagulants. Its use may be reserved for specific clinical situations or in regions where other anticoagulants are not readily available or affordable. Careful patient selection and close medical supervision are vital when phenindione is prescribed.