Immune thrombocytopenia due to antazoline (Antistina).

Antazoline (Antistina)-induced thrombocytopenic purpura occurring on three occasions in a 21-year-old woman is reported. After withdrawal of the drug ther recovered promptly. In vitro investigation demonstrated the presence of an antibody in serum, which in association with antazoline caused complement fixation when added to test platelets. Also platelet agglutinins could be detected in the patient's serum when antazoline was added. The reactions were drug specific and they could still be demonstrated 9 months after the last exposure to the drug.