Single Dose of Antibiotic as Effective as Multiple Doses for Treating Early Syphilis, Study Finds

Recent clinical research has demonstrated that a single injection of the antibiotic benzathine penicillin G (BPG) can effectively treat early syphilis, matching the success rate of the traditional three-dose regimen. The study, published in the New England Journal of Medicine, involved 249 participants across ten U.S. sites, most of whom were men and a significant portion living with HIV.

Participants were randomly assigned to receive either one intramuscular injection of 2.4 million units of BPG or three weekly injections of the same dosage. Follow-up blood tests measured the serologic response to treatment after six months. Results showed that 76% of the single-dose group exhibited successful treatment responses, compared to 70% in the three-dose group. The difference was not statistically significant, indicating that the single-dose regimen is equally effective.

This finding has important implications for patient care, as the single-dose approach simplifies treatment and could improve adherence, especially given the burden associated with multiple clinic visits. However, one participant developed neurosyphilis shortly after treatment initiation and was excluded from the analysis. The study also reported three serious adverse events unrelated to the medication.

Syphilis remains a significant public health concern, with increasing cases reported in the U.S., including over 200,000 new infections in 2023. If untreated, syphilis can cause severe complications, including neurological damage, organ damage, and adverse pregnancy outcomes. The antibiotic BPG, a mainstay treatment for syphilis, faces global shortages, though it is currently being imported into the U.S. to address supply issues.

The research highlights the potential for a more streamlined treatment strategy, which could lead to better patient outcomes and easier management of syphilis cases. Further studies are needed to evaluate whether this abbreviated regimen can be effectively applied across all stages of syphilis, including latent and late stages.

Source: https://medicalxpress.com/news/2025-09-dose-antibiotic-early-syphilis-doses.html