Warfarin

Warfarin:
• takes up to 72 hours to be effective (oral)
• Vitamin K antagonist – works by blocking the reduction of vitamin K epoxide (needed as a co-factor in synthesis of clotting factors II, VII, IX, X)
• usually used for longer term prophylaxis of venous thrombosis, thromboembolism – especially in patients with prosthetic heart valves and during atrial fibrillation
• absorbed rapidly when taken orally
• adverse effects - haemorrhage