TreatmentUpdate 55 - Vol. 7, No. 1 - January 1995
Sean Hosein

For treating patients with syphilis, the CDC (Centers for Disease Control and Prevention, Atlanta, Georgia) recommends using the antibiotic penicillin. Penicillin may not work in some patients and others may be allergic to it. Alternatives include ceftriaxone, tetracyclines and erythromycin. The CDC recommends that erythromycin should only be used for early treatment of syphilis where the patient can be monitored for 12 months. Azithromycin is an antibiotic that is 'related' to erythromycin and clarithromycin which some doctors use to treat patients with MAC and 'toxo' (toxoplasmosis). The company that sells azithromycin, Pfizer, has been studying the effect of azithromycin on subjects with primary and secondary syphilis. In previous work azithromycin can block the growth of T. pallidum (the cause of syphilis) and is effective in treating rabbits with syphilis.

* STUDY DETAILS

All 16 subjects were adults (10 male and 6 female) and the doctors recruited them from a clinic that specialized in the treatment of sexually transmitted diseases. Subjects were supposed to take 500 mg/day of azithromycin "for 10 days." Over the next 6 months most subjects returned to the clinic for observation and lab tests. Three subjects did not return for follow-up visits.

* RESULTS

According to the researchers, 11 subjects were "cured". The doctors based their diagnosis on the results of blood tests. As well, subjects who recovered usually had their symptoms (such as sores on their genitals, swollen lymph nodes and rash) clear. Two other subjects were not cured; either they never recovered or were re-infected.

* TOXICITY

Five subjects had some side effects including nausea, vomiting, "mild cramps, loose stools or diarrhea." Subjects described these symptoms as "mild" except for the one subject who vomited. No toxicity to the bone marrow, liver or kidney was detected.

* HIV

It is not clear what will happen to other patients with both HIV and syphilis who are treated with azithromycin. Some researchers note that there is a complex interplay between T. pallidum and the irnmune system. As well, diagnostic technology for syphilis generally seems not to have advanced the way tests for some other diseases have. Perhaps better tests may make clear what happens when HIV+ patients become infected with T. pallidum.

REFERENCES:

1. Verdon MS, Handsfield HH and Johnson RB. Pilot study of azithromycin for primary and secondary syphilis. Journal of Infectious Diseases 1994;19:486-488.

2. Fitzgerald TJ. The Th1/Th2-like switch in syphilitic infection: is it detrimental? Infection and Immunity 1992;60(9):3475- 3479.

3. Riley BS, Oppenheier-Marks, Rodolf JD and Norgard MU. Virulent treponema pallidum promotes adhesion of leucocytes to human vascular endothelial cells. Infection and Immunity 1994;62(10):4621-4625.

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Copyright © 1995 - TreatmentUpdate. Reproduced with permission. Reproduction of this article (other than one copy for personal reference) must be cleared through the Editor, The Canadian AIDS Treatment Information Exchange, 555 Richmond St. West, Suite 505, Box 1104, Toronto, ON, M5V 3B1 • Phone: 416-203-7122 • Toll Free: 1-800-263-1638 • Fax: 416-203-8284  http://www.catie.ca