Nafcillin-Induced Interstitial Nephritis

To the Editor.— Acute interstitial nephritis caused by any drug is probably a rare drug reaction. Methicillin sodium is the most commonly reported penicillin derivative associated with nephritis, with more than 100 cases being reported.1Reexacerbation (ie, cross sensitivity) with nafcillin, ampicillin, and cephalothin administration has been reported (1973;225: 178; 1974;227:255).2Although histological confirmation was not obtained, this is a probable case of nafcillininduced interstitial nephritis. Report of a Case.— A 60-year-old man was admitted to the orthopedic unit of Memorial Hospital Medical Center with a painful swollen right knee. He had a 40-year history of hypertension, rheumatoid arthritis, and coronary artery disease, but no renal disease. Therapy with indomethacin, 100 mg/24 hr, and allopurinol, 200 mg/24 hr, was started. Medicationscontinued from before admission included propranolol hydrochloride, 160 mg/24 hr, isosorbide dinitrate, 160 mg/24 hr, and nitroglycerin as needed. On the second day of hospitalization, knee aspirate