Products
Phenprocoumon is commercially available in tablet form (Marcoumar). It has been approved in many countries since 1953. Warfarin (Coumadin) is more common in some countries.
Structure and properties
Phenprocoumon (C18H16O3, Mr = 280.32 g/mol) is a derivative of 4-hydroxycoumarin and a racemate. The -enantiomer is pharmacologically more active. Phenprocoumon exists as a fine, white, crystalline powder that is practically insoluble in water.
Effects
Phenprocoumon (ATC B01AA04) has anticoagulant properties. It inhibits the formation of blood-clotting factors whose synthesis is dependent on vitamin K (factors II, VII, IX, and X). The effects are based on inhibition of regeneration of vitamin K in the vitamin K epoxide cycle. The drug target is vitamin K epoxide reductase complex 1 (VKORC1). There is a delayed onset of action after 36 to 72 hours. Full efficacy is achieved after five to seven days. Phenprocoumon has a long half-life of 160 hours (approximately 6.5 days).
Indications
- For the prevention and treatment of thromboembolic diseases (thromboprophylaxis, thrombosis, embolism, myocardial infarction).
- Long-term treatment of myocardial infarction when there is an increased risk of thromboembolic complications.
Dosage
According to the drug label. The dose is adjusted individually and continuously monitored and adjusted with the prothrombin time (INR, Quick).
Contraindications
Numerous precautions must be observed during use. Full details can be found in the SmPC.
Interactions
Phenprocoumon is metabolized primarily by CYP2C9 and CYP3A4. Numerous other agents and substances may potentiate or attenuate its effects (see SmPC).
Adverse effects
The most common potential adverse effects include bleeding. Because these can be life-threatening, precautions must be followed carefully. Phenprocoumon has a narrow therapeutic range. Vitamin K1 (phytomenadione) is used as an antidote.
