Absence of nafcillin-associated nephritis. A prospective analysis of 210 patients

In a prospective study of 210 consecutively seen patients receiving nafcillin, no patient's therapy was discontinued because of clinically manifested or suspected nephritis. Administration of nafcillin was discontinued because of an adverse reaction in only two patients, one with a rash and one with neutropenia. In seven of the ten patients in whom renal dysfunction developed during treatment, renal function improved while the patients continued to receive nafcillin. In the remaining three patients, renal failure was attributed to other factors including rhabdomyolysis and myoglobinuria, gastrointestinal hemorrhage and hypotension, and what appeared to be aminoglycoside toxicity. No renal biopsy studies were done because none were clinically indicated. Although the results of this study do not rule out the possibility that nafcillin may induce nephritis, if it does occur it appears in such a mild form-manifested solely as urinary sediment abnormalities-or so infrequently that it was not detected in this group of patients. In four patients, leukopenia could not be explained on any basis other than nafcillin administration.