Background There is no UK guidance specifically for the management of rectal Chlamydia trachomatis yet there is documented treatment failure with single-dose azithromycin suggesting that test of cure (TOC) and alternative treatment may be needed.

Objectives To evaluate the efficacy of single-dose azithromycin compared with 1 week of doxycycline in the treatment of rectal C trachomatis.

Methods Data were collected prospectively on all patients diagnosed with rectal C trachomatis who received azithromycin 1 g stat between 1 January and 30 June 2010 and between 1 October 2010 and 31 March 2011 following a local change in treatment protocol to 1 week of doxycycline 100 mg twice a day. Information was collected on gender, concurrent sexually transmitted infections, treatment received, re-infection risk, re-treatment and TOC at 6 weeks.

Results 11 patients (26.2%) had a positive TOC following treatment with stat azithromycin. The risk of re-infection was excluded in two, identifying nine of the 11 (81.8%) as treatment failures. Two patients had a positive TOC following treatment with 1 week of doxycycline, both were found to have a risk of re-infection. There was a significantly higher treatment failure rate in patients receiving azithromycin (p=0.0025).

Conclusions A higher treatment failure rate was found following azithromycin for rectal C trachomatis than previously published. If azithromycin is used for treatment of rectal C trachomatis, TOC may be required or alternative treatment with doxycycline may be preferable, but further data are required.