Chemoprophylactic and bactericidal efficacy of 80 mg gentamicin in a single and once-daily dosing.

OBJECTIVE: The objective was to examine the biodistribution, the chemoprophylactic, and the bactericide efficacy of 80-mg gentamicin single or once-daily dosing.

STUDY DESIGN: Ninety-six patients who had had cesarean section or gynecological surgery received 80 mg gentamicin for chemoprophylaxis. A second group of 92 patients with Gram-negative infection received once-daily 80-mg gentamicin intramuscularly, combined with cefoxitin or ceforanide, for 5 days. Gentamicin serum and tissue concentration was determined 1 h after the first administration.

RESULTS: The chemoprophylactic efficacy of gentamicin was 93.7%. The treatment efficacy was high in patients with chorioamnionitis and endometritis (92.9%), moderate in those with wound infection (69.5%), and less effective in those with septicemia (55.6%). Twenty-six percent of patients continued with antibiotics for infection control. The mean serum level was 4.48+/-0.49 and 5.56+/-0.66 microg/ml in obstetrical and gynecological patients respectively (p>0.05). Serum levels >4 microg/ml were achieved in 91% of patients.

CONCLUSIONS: A single dose of 80 mg gentamicin offers chemoprophylaxis and achieves therapeutic serum-concentrations 1 h after administration. The 5-day combination of once-daily 80 mg gentamicin with a second-generation cephalosporin is effective in patients with chorioamnionitis and endometritis, but only moderately effective in those with wound infections and septicemia.