Ranitidine-lnduced Granulocytopenia: Recurrence with Cimetidine Administration

quently with cimetidine administration (1). Ranitidine hydrochloride, the newest ^-antagonist in use, has gained widespread application because of its longer dos-ing interval and relative lack of serious adverse reactions (2). We report a case of reversible, ranitidine-induced granulocytopenia with bone marrow findings simulating those of acute promyelocytic leukemia that recurred after cimetidine was administered. A 61-year-old white man was hospitalized with fever and granulocytopenia on 10 October 1986. Five months earlier a craniotomy was done with partial resection of a grade IV astro-cytoma. Postoperatively, the patient received 5000 rad whole-brain irradiation and phenytoin therapy, 300 mg daily, was be-gun. Three weeks before the October hospitalization, ranitidine, 150 mg twice daily, had been prescribed for treatment of gastri-tis. On hospitalization, the patient was acutely ill with a tempera-ture of 39 °C. Total leukocyte count was 0.9 X 10VL; hemo-globin, 132 g/L; hematocrit, 0.39; platelets, 263 X 10VL; and differential fractions, 0.02 neutrophils, 0.04 band forms, 0.71 lymphocytes, 0.15 monocytes, and 0.01 promyelocytes. The bone marrow was hypercellular with a predominance of pro-myelocytes. Ranitidine and phenytoin treatment was discontin-ued and broad-spectrum antibiotics and phenobarbital were giv-en. Five days later the leukocyte count was 9.6 X 109/L with a normal differential. The patient was discharged with instruc-tions to take cimetidine, 300 mg four times daily. One month later the patient was hospitalized at the Phoenix Veterans Administration Medical Center with fever and granu-locytopenia. Leukocyte count was 1.1 X 109/L; hemoglobin