In proposed guidance published in the Federal Register, CDC is advising clinicians to offer gay and bisexual men and transgender women more access to doxycycline, a widely used tetracycline antibiotic, as post-exposure prophylaxis (PEP).
Individuals could use the drug after engaging in unprotected sex to reduce their risk of contracting gonorrhea, chlamydia, or syphilis. Research studies indicate that a treatment regimen known as “doxy PEP,” consisting of a single, 200-mg dose of doxycycline taken no more than 72 hours after unprotected sex, can curb the transmission of chlamydia and syphilis by nearly 80%, and gonorrhea by roughly 50%.
“Doxy PEP is moving STI prevention efforts into the 21st century,” said Jonathan Mermin, director of CDC’s National Center for HIV, Viral Hepatitis, STD, and TB Prevention, in a statement. “We need game-changing innovations to turn the STI epidemic around, and this is a major step in the right direction.”
CDC has been developing the guidance for more than a year, and wants feedback on the proposed guidance within 45 days.
In the DoxyPEP trial, researchers divided men who have sex with men and transgender women into two groups, with one group receiving doxycycline following unprotected sexual activity and a second group of those who did not. Among people who did not receive the antibiotic, their STI rate was 30% per quarter. Participants in the doxycycline arm received a median of four doses of the drug over the course of a month, while some received as many as 10 doses.