Nafcillin-induced neutropenia in children.

Neutropenia developed in three pediatric patients treated intravenously with nafcillin. This association has not been, to our knowledge, previously reported in children. One of the patients is the youngest reported who had neutropenia associated with any penicillin; another patient had a prolonged recovery. The literature pertaining to marrow suppression by all penicillins is reviewed. This usually occurs 10 to 25 days after the inception of high-dose intravenous therapy and resolves when the penicillin therapy is discontinued. An absolute neutrophil count of less than 1,000/ml is an indication to change to an antibiotic other than a penicillin. Children receiving intravenous penicillins should have WBC counts with differential analysis two to three times a week.