Pilot study of azithromycin in the treatment of genital donovanosis.

OBJECTIVES To determine the effectiveness of azithromycin, an azalide antibiotic with long tissue half-life, in a pilot study of patients with genital donovanosis in the Northern Territory, Australia. DESIGN Patients with histologically confirmed donovanosis were randomised to receive one of two open-label azithromycin dosage regimens: Regimen A--1.0 g once weekly for 4 weeks; or Regimen B--500 mg daily for 7 days. Patients were assessed at 6 weeks and classified as either "cured", "improved" or "failed". RESULTS Seven patients received regimen A and 4 received regimen B. Six weeks after commencing treatment the genital ulcers of four patients receiving regimen A and one patient receiving regimen B had healed; the lesions of the other six patients (3 in each regimen) were "improved". No patient failed to respond and no significant adverse reaction was recognised. The eleven patients were reviewed after completing the six-week trial; all lesions had re-epithelialised without further antibiotic treatment, no relapses had occurred, the longest follow-up period being seven months. A further 17 patients with donovanosis who were unable to meet the entry criteria were also treated successfully with azithromycin during the study period. CONCLUSIONS This is the first time that azithromycin has been shown to have clinical activity against donovanosis. Poor compliance with prolonged courses of antibiotics is one of the major barriers to control of the disease. Intermittent or short-course therapy, made possible by the long tissue half-life of the drug, could facilitate control of donovanosis in endemic populations if the high cost of medication can be addressed.