Severe leukopenia and mild thrombocytopenia after chronic bromocriptine (CB-154) administration

A 23-year-old woman was receiving bromocriptine (CB-154, 7.5-10 mg/day, for a hyperprolactinemic galactorrhea-amenorrhea syndrome. She also had insulin-dependent diabetes. After three months the bromocriptine therapy was stopped because she developed severe leukopenia (leukocyte counts about 1,800/cu mm) and mild thrombocytopenia (platelet count about 130,000/cu mm). Five months after stopping the bromocriptine therapy, the leukocyte count returned to normal (4,400/cu mm), as did the platelet count (238,000/cu mm). Prior to bromocriptine therapy, the patient's leukocyte and platelet counts ranged between 5,500 and 6,000/cu mm and 250,000 and 300,000/cu mm, respectively. While taking bromocriptine she was on insulin maintenance therapy and took no other drugs. Regular menses had returned and spontaneous galactorrhea had disappeared during bromocriptine therapy, and serum prolactin levels became normal. After stopping bromocriptine therapy the patient again became basally hyperprolactinemic and amenorrheic, with spontaneous galactorrhea. The article discusses possible mechanisms of this hematologic reaction.