Tetracycline in nongonococcal urethritis. Comparison of 2 g and 1 g daily for seven days.

In a previous study treatment with minocycline 100 mg orally every day for seven days was as effective for nongonococcal urethritis (NGU) as 200 mg for seven days or 100 or 200 mg for 21 days. In this prospective, randomised study men with NGU received tetracycline either 500 mg or 250 mg four times daily for seven days. of 200 men initially enrolled, Chlamydia trachomatis was isolated from 40% and Ureaplasma urealyticum from 48%. Eight of 10 homosexual men compared with 39 (21%) of 190 bisexual or heterosexual men had negative culture results for both C trachomatis and U urealyticum (x2 = 15.5, P < 0.0005). U urealyticum was isolated more frequently from chlamydia-negative men and from men with 10 or fewer sex partners during their lifetime. Both regimens were equally effective in their in-vivo activity against C trachomatis and U urealyticum. Failure rates were similar with the two regimens. More obvious failure with purulent or profuse mucoid discharge and pyuria occurred more frequently with the 250-mg regimen (20% of 76 men on the 250-mg regimen compared with 7% of 67 men on the 500-mg regimen; x2 = 4.45, P < 0.05). Failure occurred more frequently in men who were initially chlamydia-negative and in men in whom U urealyticum persisted after medication. Thus, the 250-mg regimen appeared to be as effective as the 500-mg regimen in the initial treatment of NGU. However, one-third of men had persistent or recurrent urethritis with these regimens, and there is a need for antimicrobial agents with greater in-vivo activity, especially against chlamydia-negative NGU.