Nafcillin Nephritis

To the Editor.—Methicillin, penicillin, and ampicillin have all been implicated in producing interstitial nephritis,1 and these cases represent a doserelated hypersensitivity to penicillin derivatives.2 We report a case of methicillin nephritis that recurred upon administration of nafcillin.Report of a case.—A 6-year-old white boy, with a 12-day history of fever, pain, and swelling of the left shoulder, had no prior history of drug allergy and had received penicillin for a sore throat some years previously. On admission his temperature was 39.5° C, with erythema, induration, and decreased range of motion of the left shoulder, and the white blood cell (WBC) count was 11,700/cu mm with 79% neutrophils and 1% eosinophils. Urinalysis showed no protein, cells, or casts and the creatinine clearance was 107 ml/min. The osteomyelitis and pyarthrosis of the left shoulder was found due to penicillin-resistant Staphylococcus aureus.Methicillin (250 mg/kg/day) was administered intravenously with