September 10, 2019 | ALEXANDRA WARD
As uptake of pre-exposure prophylaxis (PrEP) to prevent HIV infection increases, so does the rate of some sexually transmitted infections (STIs), particularly among gay, bisexual, and other men who have sex with men (MSM), recent studies show. Because of this alarming trend, researchers are exploring prophylactic options for bacterial STIs, including syphilis and chlamydia.
A group of international academic and government researchers conducted a review, published in Clinical Infectious Diseases, to examine current research, knowledge gaps, and challenges related to doxycycline prophylaxis for preventing bacterial STIs.
“The United States is experiencing its worst [sexually transmitted infection] epidemic in more than a generation. Syphilis is at its highest level in more than 25 years. Cases of congenital syphilis and newborn deaths due to syphilis are on the rise,” Jeffrey Klausner, MD, professor of medicine in the Division of Infectious Diseases and the Global Health Program at UCLA’s Fielding School of Public Health, and author of the study, told Contagion®. “We urgently need new strategies to control sexually transmitted diseases like syphilis.”
The research team identified 2 small, short-term, randomized, controlled trials demonstrating high efficacy of doxycycline prophylaxis, and noted 5 additional clinical studies that are ongoing.
In one of the small open-label pilot studies reviewed by the team, 30 HIV-positive men who had previous syphilis infections were randomized 1:1 to receive 100 mg of doxycycline daily as pre-exposure prophylaxis (PrEP) for 48 weeks versus a control group that received a financial incentive-based behavioral intervention. In the doxycycline PrEP group, there was a 73% reduction (p = .02) in syphilis, Neisseria gonorrhoeae, and Chlamydia trachomatis infections.
“Doxycycline has been used to prevent many infectious diseases, including Lyme disease, leptospirosis, and malaria,” Klausner said. “Doxycycline is also a recommended alternative treatment for syphilis. Doxycycline is a first-line treatment for chlamydia. We were surprised at how well it worked, [with] a 73% reduction in syphilis, whether as a daily dose or as a double dose once after sex.”
Doxycycline, a tetracycline that has been around since the 1950s, is generally well-tolerated, safe, and inexpensive. Infectious disease clinicians who care for patients at high risk for STIs should consider doxycycline, either daily or after sex, as a strategy to reduce the risk of syphilis, advises Klausner.
"Physicians administering HIV PrEP programs or patients should monitor the prevalence of syphilis in their patients and consider whether there are also patients who could benefit from the use of doxycycline prophylaxis," he concluded.
From: https://www.contagionlive.com/news/doxycycline-prophylaxis-an-effective-option-for-bacterial-stis