Introduction
Chlamydia trachomatis (C trachomatis) is the most commonly reported bacterial sexually transmitted infection (STI).
Aim
To compare a single dose of azithromycin with a 7-day course of doxycycline for the treatment of anorectal C trachomatis infection in women with concurrent vaginal infection
Patient Profile
Sexually active adult women (>18 years) with a positive C trachomatis vaginal swab
Methods
- Multicentre, open label, randomised, controlled, superiority trial
In the azithromycin group, participants took four 250-mg tablets as a single dose (ie, a single 1-g dose of azithromycin), with or without food
In the doxycycline group, women were instructed to take a single 100-mg tablet in the morning and in the evening for 7 days (i.e., 100 mg of doxycycline twice per day for 7 days), at mealtimes with a glass of water and at least 1 h before bedtime
Study Outcomes
- The primary outcome was the microbiological anorectal cure rate defined as a C trachomatis-negative nucleic acid amplification test (NAAT) result in anorectal specimens 6 weeks after treatment initiation among women who had a baseline C trachomatis-positive anorectal NAAT result
- Secondary outcome measures were the prevalence of anorectal C trachomatis infection concurrent with urogenital infection
Results
- 7-day course of doxycycline was significantly more efficacious than a single 1-g dose of azithromycin for the treatment of anorectal C trachomatis infection concurrent with vaginal infection (figure1)
- At 6 weeks, 16 women were C trachomatis-negative in the vaginal swab but C trachomatis-positive in the anorectal swab and had a visit rescheduled at 4 months.
- Four participants from doxycycline group and 2 participants from azithromycin group cleared their anorectal infection at 4 months
- Adverse events possibly related to treatment were reported in 53 (12%) of 456 women
- Doxycycline group=24 (11%) of 228
- Azithromycin group=29 (13%) of 228
Conclusion
- The study demonstrated higher efficacy of 1-week course of doxycycline than of single dose of azithromycin for the treatment of anorectal C trachomatis infection.
- The finding suggested that doxycycline should be the first-line therapy for C trachomatis infection in women.
Reference
Lancet Infect Dis. May 9, 2022, https://doi.org/10.1016/ S1473-3099(22)00148-7