Amikacin therapy of infections in neutropenic patients.

Amikacin, a new aminoglycoside antibiotic, was utilized in the treatment of 49 cases of infection which occurred in 39 neutropenic cancer patients. Thirty-four patients (69 per cent) responded to this antibiotic. Pneumonia and septicemia were the most common types of infection treated and the response rates were 65 per cent and 75 per cent, respectively. Gram-negative bacili were responsible for 93 per cent of the identified infections and 74 per cent responded. E. coli, Ps. aeruginosa, and organisms of the Klebsiella-Enterobacter-Serratia group were the most common gram-negative bacilli causing infection. Responses were more frequent among patients who maintained higher serum concentrations of antibiotic, but the differences were not statistically significant. Patients with severe neutropenia (less than 100 neutrophils/mm3) had a response rate of 68 per cent. Toxicity was manifested as azotemia and hearing loss which occurred in 13 per cent and 6 per cent, respectively. However, toxicity was directly related to serum concentration and to the number of treatments with amikacin. This antibiotic is of potential importance because of its efficacy against gram-negative bacilli infections. Best results were obtained when sufficient drug was given as a continuous intravenous infusion to maintain serum concentrations of about 15 mu g/ml.