Use of rifampin for the treatment of urinary tract infections.

The pharmacokinetic and microbiologic properties of rifampin are such that the antibiotic appears suitable for the treatment of urinary tract infections. However, its use alone for this indication is associated with an unacceptably high rate (approximately 30%) of acquisition of high-level resistance during therapy-an event that results in the failure of treatment. The combination of rifampin with another suitable antibiotic prevents this emergence of resistance. In vitro, pharmacokinetic, epidemiologic, and clinical studies with a combination of rifampin and trimethoprim (300 mg of rifampin: 80 mg of trimethoprim) both in England and in other countries have shown that this combination is effective and safe for the treatment of recurrent urinary tract infections. Provided that careful laboratory controls are used, the combination of rifampin and trimethoprim is a useful addition to the list of antibiotics available for the treatment of this condition.