Cinoxacin: new antimicrobial agent for urinary tract infections.

One hundred forty-six patients with recurrent urinary tract infections were treated with 500 mg. of cinoxacin twice daily for seven to fourteen days. Satisfactory clinical response occurred in 94 per cent. Of the 100 patients with significant pretherapy bacteriuria (greater than or equal to 10(4) organisms/ml. of urine), 65 had complicated infections. Approximately the same per cent of patients with (90 per cent) as without (94 per cent) complicating conditions had a satisfactory clinical response to treatment. The pathogen was eliminated in a higher percentage of patients without underlying disease (90 versus 80 per cent), and infections recurred less frequently in this group (3 versus 14 per cent). Emergence of resistance by initially susceptible organisms during the course of therapy occurred in 4 of 76 patients (5 per cent). A satisfactory clinical response occurred in all 46 patients with an initial colony count of less than 10(4) organisms/ml. urine. Only 1 patient in this group was a bacteriologic failure. Adverse effects of a relatively wild nature were seen in 4 of 146 patients (2.7 per cent). Successful eradication of 12 of 23 urinary infections in patients whose pathogens were resistant to the 30-microgram. cinoxacin disk suggests that the 100-microgram. disk may be more realistic for determining bacterial susceptibility by the disk diffusion method in view of the very high urinary concentration of the drug.