Clindamycin therapy for Chlamydia trachomatis in women

The population for this study consisted of 4013 sexually active women seen for family planning. Culture for Chlamydia trachomatis yielded an isolation rate of 6.1%. Women aged 16 to 25 accounted for 81.7% of the C. trachomatis infections, while those younger than 16 or older than 35 accounted for only 2.4% of the infections. Of the 246 patients whose cultures were positive for C. trachomatis, 159 (65%) were asymptomatic. The incidence of C. trachomatis was 11.2% among those with symptoms but only 6.4% among the asymptomatic group. Among 63 patients with Neisseria gonorrhoeae (who were excluded from the study), 26 (41.3%) also were infected by C. trachomatis. There were no microbiologic drug failures with erythromycin or clindamycin. Of 56 patients who enrolled in the clindamycin arm of the protocol, 48 (85.7%) completed therapy and experienced microbiologic and clinical cures. In contrast, erythromycin therapy was completed by only 25 of 57 women (43.9%) enrolled. The number of side effect failures for erythromycin was 22 of 57 (38.6%). This was more than five times the number of side effect failures for clindamycin (4 of 56, or 7.1%).