A single dose of penicillin is effective for treating early-stage syphilis infections, according to results of a multisite clinical trial that included researchers from Indiana University School of Medicine.
Infectious disease specialists have long debated how many doses of benzathine penicillin effectively treat early syphilis — when the infection is in its primary, secondary and early latent stages. While a single injection has been the widely accepted treatment since the 1950s, some doctors have questioned whether additional injections or higher doses of penicillin would be better treatment options, especially for those with co-existing conditions, like HIV.
These new findings — which were published in the New England Journal of Medicine and co-authored by Teresa Batteiger, MD, an associate professor in the Department of Medicine's Division of Infectious Diseases — reaffirms that a single dose is sufficient for patients with and without HIV. The results are a victory in the wider effect of antimicrobial stewardship.
The trial took place at 10 sites across the country and involved 249 patients — including 153 with HIV infections — who were randomly selected to receive either one or three weekly 2.4-million-unit doses of benzathine penicillin, according to the report.
“In the one-dose group, a serologic response at 6 months was observed in 76% of participants who had HIV infection and 76% of those who did not, and in the three-dose group, a serologic response at 6 months was observed in 71% of participants who had HIV infection and 70% of those who did not,” the study states.
Those noninferior results are encouraging for both doctors and patients for several reasons, according to the authors.
First, there have been a number of penicillin shortages in recent years due to increased rates of syphilis infections and various drug recalls, the authors note. Using fewer doses of penicillin for early syphilis treatment will help to ensure the antibiotic remains available when its most needed.
Next, for patients, injections of penicillin can be very painful, and fewer doses means less discomfort. While most participants reported pain at the injection site, according to the study, the rate jumped from 76% of those with a single-dose treatment to 85% of those with a three-dose treatment.
But perhaps most importantly, the study notes that its results may ensure that antibiotics won’t be over-prescribed in these types of cases, which helps in the larger fight against antibiotic resistance.
In an effort referred to as antimicrobial stewardship, or antibiotic stewardship, clinicians, researchers and other medical experts across the globe are regularly working together to strike a balance between effective antibiotic treatment and the unnecessary or over-use of these types of medicines. Resistance to antibiotics happens when infection-causing bacteria changes over time and no longer responds to the medicine once designed to fight it, and it’s seen as one of the top public health threats facing the world.
Knowing that one dose of 2.4 million units of benzathine penicillin G works effectively in early syphilis cases saves doctors from prescribing the additional shots that would result in a total of 7.2 million units after the three-dose treatment, the study states.
Antimicrobial stewardship is an important part of the research work done in the Division of Infectious Diseases. Division faculty conduct basic science research into bacterial pathogenesis, HPV, and malaria, while clinical research is conducted in prevention, treatment and implementation science research in HIV, other sexually transmitted infections, malaria and reproductive health infections.
Many clinical trials into STD treatment and prevention take place at the Bell Flower Clinic in Indianapolis, in partnership with the Marion County Health Department. Batteiger serves as the Bell Flower Clinic’s STD Clinic Co-Program Development Director.
