Dose-related levodopa-induced haemolytic anaemia.

A 71-year-old white man developed direct antiglobulin positive haemolytic anaemia after 16 months of levodopa therapy for Parkinson's disease. Immunoglobulin G autoantibodies directed against Rh antigens were found in the patient's serum and on his erythrocytes. Reduction of levodopa dosage to one sixth with the aid of a peripheral decarboxylase inhibitor (benserazide) largely eliminated autoimmune haemolysis while maintaining adequate control of neurologic symptoms.