Nafcillin-Induced Agranulocytosis

ADVERSE REACTIONS to the penicillins are relatively common1and are clinically expressed in various ways,2probably through different mechanisms.3An infrequent complication of penicillin therapy is agranulocytosis, first reported with the semisynthetic penicillin, methicillin.4Nafcillin (6-[2-ethoxy-l-naphthamido] penicillin) is structurally similar to methicillin. However, to our knowledge, reports of agranulocytosis resulting from nafcillin have not been published. Report of a Case A 44-year-old housewife was admitted to the Medical College of Virginia Hospitals on Sept 23, 1974, with a partially treatedStaphylococcus aureusendocarditis with tricuspid-valve involvement and septic pulmonary emboli. On physical examination she appeared weak, but well nourished and in no acute distress. Her temperature was 39.2 C (102.6 F); blood pressure, 105/70 mm Hg; and pulse rate, 110 beats per minute. Prominent jugular pulsations ("v" waves) were noted. A grade 3/6 harsh systolic murmur was heard at the second left intercostal space. The rest