A phase III equivalence trial of azithromycin versus benzathine penicillin for treatment of early syphilis

J Infect Dis. 2010 Jun 1;201(11):1729-35. doi: 10.1086/652239.

Abstract

Background: Syphilis remains an important source of morbidity worldwide. Long-acting penicillin is the only therapy currently recommended for syphilis in much of the world. Because of hesitation to use penicillin for fear of anaphylaxis, there is a need for an effective, well-tolerated alternative to penicillin for syphilis therapy.

Methods: This multicenter, randomized clinical trial was conducted in clinics for the treatment of persons with sexually transmitted diseases. We compared serological cure rates for human immunodeficiency virus (HIV)-negative persons with early syphilis treated with azithromycin at a dosage of 2.0 g administered orally as a single dose with cure rates for those treated with benzathine penicillin G at a dosage of 2.4 million units administered intramuscularly.

Results: A total of 517 participants were enrolled in the trial. In the intention-to-treat analysis, after 6 months of follow-up, serological cure was observed in 180 (77.6%) of 232 azithromycin recipients and 186 (78.5%) of 237 penicillin recipients (1-sided lower bound 95% confidence interval, 7.2%). Nonserious adverse events were more common among azithromycin recipients than they were among penicillin recipients (61.5% vs 46.3%), and such adverse events were accounted for, in large part, by self-limited gastrointestinal complaints.

Conclusions: In this trial, the efficacy of azithromycin at a dosage of 2.0 g administered orally was equivalent to that of benzathine penicillin G for the treatment of early syphilis in persons without HIV infection.

Trial registration: ClinicalTrials.gov NCT00031499.

Publication types

  • Clinical Trial, Phase III
  • Comparative Study
  • Multicenter Study
  • Randomized Controlled Trial
  • Research Support, N.I.H., Extramural
  • Research Support, U.S. Gov't, Non-P.H.S.

MeSH terms

  • Adolescent
  • Adult
  • Anti-Bacterial Agents / administration & dosage
  • Anti-Bacterial Agents / therapeutic use*
  • Azithromycin / administration & dosage
  • Azithromycin / therapeutic use*
  • Female
  • Humans
  • Male
  • Middle Aged
  • Penicillin G Benzathine / administration & dosage
  • Penicillin G Benzathine / therapeutic use*
  • Syphilis / drug therapy*
  • Treatment Outcome
  • Young Adult

Substances

  • Anti-Bacterial Agents
  • Azithromycin
  • Penicillin G Benzathine

Associated data

  • ClinicalTrials.gov/NCT00031499