Re-exposure to recombinant (r)-hirudin in antihirudin antibody-positive patients with a history of heparin-induced thrombocytopenia.

Patients with a history of heparin-induced thrombocytopenia (HIT) and antibodies to hirudin were re-exposed to recombinant (r)-hirudin for prophylaxis of thromboembolism. Four patients were re-exposed to 2 x 25 mg of subcutaneous r-hirudin for 8-27 d. Two patients were re-exposed once, one patient twice and one four times. Re-exposure was well tolerated in all patients and no thromboembolism occurred. Antihirudin IgG (4/4 patients), IgA and IgM (1/4 patients) antibody levels increased. Baseline ecarin clotting times showed high variability. Patients with antibodies to hirudin may be re-exposed but anticoagulant monitoring is mandatory.