Single-dose oral azithromycin versus seven-day doxycycline in the treatment of non-gonococcal urethritis in males

One hundred and twenty male patients with signs and symptoms compatible with non-gonococcal urethritis were enrolled in a prospective-randomized study to compare the efficacy and safety of a single oral-dose of 1 g azithromycin and a seven-day course of 100mg doxycycline twice-daily. Clinical examination and culture samples for Chlamydia trachomatis were performed before and approximately 8, 15 and 35 days after starting treatment. Both treatment groups were comprised of 30 chlamydia-positivc patients evaluable for efficacy. The eradication rate of C. trachomatis in baseline-positive patients at the first follow-up visit in the azithromycin group was 96% with one persistent case, and 100% in the doxycycline group. After about two weeks, there were two reoccurrences in the azithromycin group, resulting in a cumulative eradication rate of 90% with three culture-positive cases. The corresponding figure in the doxycycline group was still 100%, but there were leucocytes present in the urethral smear of two patients who later proved to be true culture-positive reoccurrences. After about five weeks, there was an additional reoccurrence in the azithromycin group leading to a cumulative eradication rate of 87%, while two reoccurrences in the doxycycline group gave a cumulative eradication rate of 93%. There was no statistically significant difference in efficacy between the single-dose azithromycin and seven-day course of doxycycline in the treatment of patients with chlamydial urethritis. The cure rate in chlamydia-negative patients was higher with azithromycin throughout the whole follow-up period. By five weeks, the cure rate in the azithromycin group was significantly higher than that in the doxycycline group (79% vs 35% P = 0.017). However, when two patients with only vague evidence of relapse (some urethral itching and/or dysuria; no leucocytes in the urethral smear) were excluded, the cure rate in the doxycycline group was about 50%, and the difference between treatment groups was no longer statistically significant. Gastrointestinal side-effects were reported in 13–14% of patients in the treatment groups; 5% of the patients in the azithromycin group experienced mild CNS symptoms such as headache and dizziness.