A phase III equivalence trial of azithromycin versus benzathine penicillin for treatment of early syphilis.
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.
Hook
Edward W
EW
University of Alabama at Birmingham and Jefferson County Department of Health, Birmingham, AL, USA. ehook@uab.edu
Behets
Frieda
F
Van Damme
Kathleen
K
Ravelomanana
Noro
N
Leone
Peter
P
Sena
Arlene C
AC
Martin
David
D
Langley
Carol
C
McNeil
Linda
L
Wolff
Mark
M
D000293:Adolescent; D000328:Adult; D000900:Anti-Bacterial Agents / Q000008:administration & dosage / Q000627:therapeutic use*; D017963:Azithromycin / Q000008:administration & dosage / Q000627:therapeutic use*; D005260:Female; D006801:Humans; D008297:Male; D008875:Middle Aged; D010401:Penicillin G Benzathine / Q000008:administration & dosage / Q000627:therapeutic use*; D013587:Syphilis / Q000188:drug therapy*; D016896:Treatment Outcome; D055815:Young Adult
D000900:Anti-Bacterial Agents; D017963:Azithromycin; D010401:Penicillin G Benzathine