Azithromycin may be ineffective in treating syphilis

Since 2000, the incidence of syphilis has increased in the United States, particularly in San Francisco, where in 2002, one of the highest incidence rates of primary and secondary syphilis in the United States has been recorded. To simplify the specific treatment of patients with early forms of syphilis, as well as for the preventive treatment of their sexual partners, a single oral administration of azithromycin has been recommended in certain guidelines. The effectiveness of such therapy has been demonstrated in several small clinical trials in patients not infected with HIV. In addition, oral administration of azithromycin is more convenient than the intramuscular injection of benzathine benzylpenicillin, recommended by the United States Centers for Disease Control and Prevention (CDC) as a first-line drug for the treatment of syphilis.

At the same time, in April 2003, the first case of ineffectiveness of azithromycin in the treatment of primary syphilis was noted, and subsequently information was collected on 7 other obvious syphilis treatment failures recorded from July 2002 to September 2003, which were analyzed San Francisco Department of Health.

The 8 patients were homosexuals who had 2 to 100 sexual partners in the previous 3 months, 5 patients were infected with HIV. The ineffectiveness of the 2 g azithromycin treatment was observed once in 3 patients with hard chancres. The remaining 5 patients received preventive treatment with azithromycin at a dose of 1 g once for seronegative forms of the disease that developed as a result of sex with patients with early forms of syphilis, but they then had seroconversion or manifestations of early syphilis.

All patients then received specific treatment with penicillin or doxycycline, the efficacy of which was confirmed clinically and serologically.

Further observations and studies are planned to determine the molecular mechanisms of macrolide resistance in strains of Treponema palludum, the risk factors for clinical ineffectiveness when using azithromycin and the possibility of using this medicine in specific categories of patients (for example, HIV-infected) for the treatment of syphilis.

The published finding and CDC recommendations point out that penicillin remains the drug of choice for the treatment of syphilis. The use of azithromycin for both preventive treatment and for the treatment of syphilitic infection should only be limited and authorized in patients with allergic reactions to beta-lactam antibiotics and only if it is possible to '' perform adequate healing control after treatment is completed.