Objective: To evaluate the use of single-dose azithromycin for empirical treatment of nongonococcal urethritis.
Design: Randomized, double-blind, multicenter trial comparing azithromycin vs doxycycline therapy, with a 2:1 randomization ratio. Patients were evaluated clinically and microbiologically for Chlamydia trachomatis and Ureaplasma urealyticum infection before therapy and at 2 and 5 weeks after study entry.
Setting: Eleven sexually transmitted disease clinics throughout the United States.
Patients: A total of 452 men aged 18 years or older with symptomatic nongonococcal urethritis of less than 14 days' duration.
Intervention: Patients were treated with either 1.0 g of azithromycin as a single oral dose or 100 mg of doxycycline taken orally twice daily for 7 days.
Main outcome measures: Clinical resolution of symptoms and signs of nongonococcal urethritis, microbiological cure of C trachomatis and U urealyticum, and occurrence of adverse experiences.
Results: Of the 452 patients enrolled, 248 in the azithromycin-treated group and 123 in the doxycycline-treated group were evaluable for clinical response. The two treatment groups were comparable in terms of age, weight, ethnic distribution, sexual preference, sexual activity, and history of prior nongonococcal urethritis or gonorrhea. Sixteen percent of the azithromycin group and 24% of the doxycycline group were culture positive for C trachomatis before therapy, while 38% and 28%, respectively, were culture positive for U urealyticum. The cumulative clinical cure rate was 81% (95% confidence interval [CI], 75% to 85%) in the azithromycin-treated group and 77% (95% CI, 69% to 84%) in the doxycycline-treated group. Clinical cure rates in the two groups were also comparable when patients were stratified by presence or absence of infection with C trachomatis or U urealyticum prior to therapy. Among those infected with C trachomatis, overall microbiological cure rates were 83% (95% CI, 65% to 94%) for azithromycin-treated patients (n = 30) and 90% (95% CI, 68% to 98%) for doxycycline-treated patients (n = 21). Among those infected with U urealyticum, overall microbiological cure rates were 45% (95% CI, 34% to 57%) for azithromycin-treated patients (n = 75) and 47% (95% CI, 30% to 65%) for doxycycline-treated patients (n = 32). Adverse reactions were generally mild to moderate and occurred in 23% of the azithromycin-treated group and 29% of the doxycycline-treated group.
Conclusions: For empirical treatment of the acute nongonococcal urethritis syndrome in men, a single oral dose of azithromycin was as effective as a standard 7-day course of doxycycline in achieving clinical cure. Further, clinical cure rates were comparable with either regimen, regardless of the presence or absence of Chlamydia or Ureaplasma infection.