Adverse effects of methicillin, nafcillin and oxacillin in pediatric patients.

68 patients (from newborns to 18 years of age) were studied prospectively for adverse effects associated with methicillin, nafcillin and oxacillin. Hematologic, liver and renal function tests were monitored before and during therapy. 3 of 28 patients receiving methicillin developed eosinophilia within 5-8 days. Of 32 patients on nafcillin, 2 had neutropenia within 4-13 days, 3 had eosinophilia within 1-4 days and 1 elevated liver enzymes on day 3. Of 8 patients receiving oxacillin, 1 developed neutropenia on day 11 and another showed elevation of liver enzymes on day 15. All abnormalities were reversible with the discontinuation of therapy. Appropriate laboratory tests should be monitored to detect an occurrence of adverse reaction to methicillin, nafcillin and oxacillin.