One-dose treatment for early syphilis appears effective

October 8, 2013

SAN FRANCISCO — Two studies presented here at ID Week 2013 suggest that one dose of benzathine penicillin is effective against early syphilis among patients with HIV.

The CDC changed its guidelines for treating early syphilis in 2010, lowering the benzathine penicillin dose from 7.2 million units, given as three doses, to a single dose of 2.4 million units.

Researchers from the Uniformed Services University of the Health Sciences, including Anuradha Ganesan, MBBS, MPH, evaluated this dose by collecting data from the US military HIV Natural History Study. They identified 741 patients who met serologic criteria for syphilis, and 439 of them experienced early syphilis. Of these, 335 patients were included for analysis. Thirty percent (n=100) received one dose of benzathine penicillin and 51% (n=172) received two or more doses. The remaining patients received other treatment.

According to Ganesan, there was no difference in the serologic responses to one dose vs. multiple doses of benzathine penicillin, and 90% of patients responded to treatment. Risk factors associated with serologic failure included older age and lower rapid plasma regain titers. In the HIV Natural History Study, the use of one dose increased since the CDC implemented its new guidelines in 2010, and the use of two or more doses declined.

“We found that response to a single dose of benzathine penicillin was similar to that observed with two or more doses,” Ganesan said during her presentation.