argatroban or lepirudin

The query "argatroban or lepirudin" refers to two distinct anticoagulant drugs, argatroban and lepirudin, both of which are direct thrombin inhibitors. Argatroban is a synthetic small molecule that reversibly binds to the active site of thrombin, inhibiting its procoagulant effects. It is primarily used for the treatment and prophylaxis of thrombosis in patients with heparin-induced thrombocytopenia (HIT) and for anticoagulation during percutaneous coronary intervention (PCI) in patients with or at risk for HIT. Lepirudin, a recombinant hirudin (a protein derived from leech saliva), is a direct and essentially irreversible thrombin inhibitor. It binds to both the catalytic and substrate-binding sites of thrombin, thereby blocking its thrombogenic activity. Lepirudin was indicated for anticoagulation in patients with HIT and associated thromboembolic disease, but its production was ceased by Bayer in 2012, leading to its discontinuation. Both drugs exert their anticoagulant effects independently of antithrombin III.