Objective: To compare the efficacy and tolerability of minocycline versus doxycycline in the treatment of nongonococcal urethritis and mucopurulent cervicitis.
Design: Randomized, double-blind trial.
Setting: Sexually transmitted disease clinics.
Patients: 151 men and 102 women with nongonococcal urethritis, mucopurulent cervicitis or whose sexual partner had either condition or a positive culture for Chlamydia trachomatis.
Interventions: Minocycline, 100 mg nightly, or doxycycline, 100 mg twice daily, each administered for 7 days.
Measurements: At each visit (days 14 3, 28 5, and 49 7) patients were questioned regarding symptoms, signs, drug compliance, and sexual contact. Cultures for C. trachomatis, Ureaplasma urealyticum, and Mycoplasma hominis were obtained at each visit.
Results: 253 patients were enrolled (133, doxycycline; 120, minocycline). Chlamydia trachomatis was initially isolated from 31% of men and 39% of women. Men with a positive smear had a higher symptom/sign score (P < 0.001) and were more likely to have chlamydia (P = 0.004). Positive endocervical smears were not associated with symptoms or signs (P > 0.2) but correlated with isolation of chlamydia (P < 0.001). One hundred sixty-two patients (64%) completed the study. The proportion with urethritis or cervicitis did not differ by treatment group at any follow-up visit (P > 0.08). Unprotected sexual contact did not affect clinical or microbiological cure rates. Adverse effects occurred more frequently in the doxycycline group (men: 43% versus 26%; P = 0.05; women: 62% versus 35%; P = 0.009). Although the proportion with dizziness did not differ by drug administered (P = 0.1), dizziness was reported more often by women (11% versus 3%).
Conclusions: Minocycline, 100 mg nightly, was as effective as doxycycline, 100 mg twice daily, each given for 7 days in the treatment of nongonococcal urethritis and mucopurulent cervicitis. Vomiting and gastrointestinal upset occurred more frequently in the doxycycline group.