Erythromycin against Chlamydia trachomatis infections. A double blind study comparing 4- and 7-day treatment in men and women.

In a double-blind controlled study the treatment of erythromycin 500 mg twice daily for seven days was compared with erythromycin 500 mg twice daily for four days in 73 men and women with uncomplicated genito-urinary chlamydia trachomatis infections. At the start of the treatment, 34 of 42 men (81%) and 15 of 31 women (48%) had symptoms suggesting the presence of chlamydial infections. There was a significantly higher bacteriological cure rate with the seven-days treatment in both men and women compared with the four days treatment at the second control visit two weeks after the start of the treatment (p less than 0.0005). The bacteriological cure rate of the women was higher than that of the men, but the results for men and women did not differ significantly. It is concluded that a four day treatment with erythromycin 500 mg twice daily can not be recommended, whereas 500 mg twice daily for seven days was shown to be effective, especially in women.