The antibiotic ceftriaxone is an effective treatment for early syphilis in pregnancy, a small study has shown.
Researchers studied the efficacy of broad-spectrum cephalosporin in 11 HIV-negative pregnant women with early syphilis and histories of penicillin allergy or skin test reactions to penicillin antigen. Gestation at the initiation of treatment was 4 to 18 weeks (Sex. Transm. Dis. 2005;32:495–8).
Three women were diagnosed with primary syphilis and eight with secondary syphilis. Those with primary syphilis received intramuscular injections of 250 mg ceftriaxone (Rocephin) once daily for 7 days. Those with secondary syphilis got once-daily injections for 10 days. The same course was repeated for both groups at 28 weeks' gestation, said Dr. Pingyu Zhou, M.D., Ph.D., and colleagues at Shanghai (China) Skin and STD Hospital.
The patients were reexamined eight times over 24 months. All completed the first course of treatment, and 8 of the 11 completed the second course.
Within 1 month of the first course of treatment, syphilitic skin lesions disappeared in all patients and did not recur in the follow-up period. Within 3 months, there was a fourfold reduction in serum rapid plasma reagin (RPR) titers with no increase in the follow-up period. Ten women developed negative RPR measures in the follow-up period.
None of the neonates had clinical or radiographic manifestations of congenital syphilis at birth or in the 2-year follow-up period. At birth, 5 infants had serum RPR measures equal to those of their mothers at delivery, but all were negative within 12 months.
Although the study is limited by its size and the fact that the patients studied were less likely to transmit syphilis to their newborns than other risk groups, the findings suggest ceftriaxone can be considered as a therapeutic alternative for the treatment of early syphilis “in the appropriate clinical setting,” the authors wrote.
There was no evidence of the necessity of the second course of therapy, Dr. Zhou and associates said.