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BLOOD AND BLOOD FORMING ORGANS › ANTITHROMBOTIC AGENTS › ANTITHROMBOTIC AGENTS › Vitamin K antagonists
clorindione
B01AA09
Adult Dosing
- Initial dose: 20 to 40 mg daily for 2 days, adjusted according to prothrombin time or INR
- Maintenance dose: 5 to 20 mg daily, tailored to maintain target INR (typically 2.0 to 3.0)
Pediatric Dosing
- Safety and efficacy in pediatric patients not established; use generally avoided
Indications
- Prophylaxis and treatment of venous thrombosis and its extension
- Prophylaxis and treatment of thromboembolic complications associated with atrial fibrillation or cardiac valve replacement
Mechanism of Action
- Vitamin K antagonist that inhibits the vitamin K epoxide reductase complex, depleting active reduced vitamin K and preventing the gamma-carboxylation of coagulation factors II, VII, IX, and X, as well as endogenous anticoagulant proteins C and S
Contraindications
- Active bleeding or hemorrhagic tendencies
- Severe hepatic impairment
- Severe uncontrolled hypertension
- Recent or planned major surgery involving the central nervous system or eye
- Pregnancy due to teratogenicity and risk of fetal hemorrhage
Adverse Reactions
- Major and minor hemorrhage
- Nausea, vomiting, diarrhea, and anorexia
- Alopecia
- Skin necrosis and purple toe syndrome (rare)
- Hypersensitivity reactions and dermatitis
Drug Interactions
- Enhanced anticoagulant effect and increased bleeding risk with CYP2C9 inhibitors (e.g., amiodarone, fluconazole), NSAIDs, antiplatelet agents, and broad-spectrum antibiotics
- Decreased anticoagulant effect with CYP2C9 inducers (e.g., rifampin, carbamazepine, barbiturates) and vitamin K supplementation
Curated Content: Needs Vetting Before Put to Clinical Use