Cimetidine and hematologic suppression: things are not always as they appear.

A 67-year-old man with a bleeding ulcer developed fever, thrombocytopenia, and neutropenia with eosinophilia coincidental to receiving 3600 mg of cimetidine. Failure to reduplicate the hematologic suppression after cimetidine rechallenge suggests the drug was not responsible for the change in circulating cells. Our patient is similar to the earlier reported cases of cimetidine-associated hematologic suppression. The role of cimetidine in these cases is impossible to determine because of the multifactorial possibilities for bone-marrow suppression. Recently, a fatal case of agranulocytosis associated with cimetidine has been reported. The possible mechanisms of granulocytopenia are reviewed, and it is suggested cimetidine may cause bone-marrow suppression by an idiosyncratic reaction. We believe the possibility of fatal aplastic anemia secondary to cimetidine is very rare and does not preclude a drug rechallenge when the benefit-risk ration warrants.