Comparing 10-day and 4-month doxycycline courses for treatment of Chlamydia trachomatis-reactive arthritis: a prospective, double-blind trial.

To compare the efficacy of a 10-day and a 4-month doxycylcine course for the treatment of Chlamydia trachomatis-reactive arthritis (Ct-ReA). Patients with active Ct-ReA were enrolled in a prospective, multicentre, double-blind, controlled clinical trial and randomised to receive doxycycline 100 mg twice daily for 10 days followed either by placebo or by continued doxycycline 100 mg twice daily over 4 months. Various clinical and laboratory parameters referring to disease activity were recorded in the beginning and at the end of treatment. 32 of 37 patients included (15 men and 17 women; mean (standard deviation) disease duration 17 (13) months completed the study; 17 were randomised to short-term doxycycline and placebo (placebo group) and 15 to prolonged treatment with doxycycline (doxycycline group) over the 4-month study period. After this time, only two patients from each group went into remission. There were no drop-outs owing to adverse events or treatment failures. The results of this study suggest that prolonged treatment with a 4-month course of doxycycline is not superior to short-term treatment over 10 days in patients with Ct-ReA.