An open label comparative study of azithromycin and doxycycline in the treatment of non-gonococcal urethritis in males and Chlamydia trachomatis cervicitis in female sex workers in an STD clinic in Singapore

Singapore Med J. 1999 Aug;40(8):519-23.


Aim of study: The aim of this study was to compare the clinical and microbiological efficacy of a single 1 gram dose of azithromycin against 1 week of doxycycline at 100 mg twice a day in the treatment of: (1) uncomplicated non-gonococcal urethritis (NGU) in male patients, and (2) culture proven Chlamydia trachomatis cervicitis in female sex workers.

Method: The subjects were 53 male patients who attended the clinic and were diagnosed to have non gonococcal urethritis based on clinical symptoms and a urethral smear, and 63 female sex workers, who had both a positive enzyme immunoassay (EIA) test and Chlamydia trachomatis cultures. Follow-up visits were made at one and two weeks post-treatment to assess efficacy, subsequent relapse and presence of side effects. The male patients were also assessed at four weeks post treatment to determine default and reinfection rates.

Results: Both azithromycin (clinical cure rates 62.5% at one week, 86.4% at two weeks in male patients; 96.6% at two weeks in female sex workers) and doxycycline (clinical cure rates 65.4% at one week, 90.9% at two weeks in male patients; 100% at two weeks in female sex workers) were effective in treating non-gonococcal urethritis and chlamydial cervicitis. Both drugs were very effective in eradicating proven Chlamydia trachomatis infections, with success in 100% of cases of Chlamydia trachomatis NGU in males, and 96.6% and 100% cure rates, for azithromycin and doxycycline respectively, in female sex workers with cervicitis. There were no statistically significant differences between the two drugs in terms of clinical efficacy, influence on default rates or subsequent risk of reinfection.

Conclusions: We conclude that a single dose of azithromycin is as effective as a one week course of doxycycline in treating non-gonococcal urethritis in males and in the elimination of Chlamydia trachomatis in females with cervicitis, with the added advantage of a convenient single dose that can be supervised.

Publication types

  • Clinical Trial
  • Comparative Study

MeSH terms

  • Adolescent
  • Adult
  • Ambulatory Care Facilities
  • Anti-Bacterial Agents / administration & dosage
  • Anti-Bacterial Agents / adverse effects
  • Azithromycin / administration & dosage*
  • Azithromycin / adverse effects
  • Chlamydia Infections / diagnosis
  • Chlamydia Infections / drug therapy*
  • Chlamydia trachomatis / isolation & purification*
  • Doxycycline / administration & dosage*
  • Doxycycline / adverse effects
  • Female
  • Gonorrhea
  • Humans
  • Male
  • Middle Aged
  • Sex Work
  • Sexually Transmitted Diseases / drug therapy
  • Singapore
  • Treatment Outcome
  • Urethritis / drug therapy*
  • Urethritis / microbiology*
  • Uterine Cervicitis / drug therapy*
  • Uterine Cervicitis / microbiology


  • Anti-Bacterial Agents
  • Azithromycin
  • Doxycycline