If taken within 72 hours of condomless sex, the common antibiotic doxycycline drastically reduces the risk of gonorrhea, syphilis and chlamydia among transwomen and gay, bisexual and other men who have sex with men, a recent study shows.
Using doxycycline like this is a form of post-exposure prophylaxis (PEP), or medicine taken after you've been exposed to a disease to help protect you from illness. Doxy-PEP is a new approach tested in part by Annie Luetkemeyer, MD, professor of infectious diseases at Zuckerberg San Francisco General Hospital and UCSF, alongside colleagues from the San Francisco Department of Public Health and the University of Washington.
Scientists hope that offering doxy-PEP can stem rising rates of these STIs. More than 2.5 million STI cases were diagnosed in the U.S. in 2021 alone. We asked Luetkemeyer what people need to know about doxy-PEP.
Who can take Doxy-PEP?
Doxy-Pep is an option to reduce the risk of syphilis, gonorrhea and chlamydia for transwomen as well as gay, bisexual or other men who have sex with men and who have had at least one of these STIs in the past 12 months. Clinicians can also consider prescribing doxy-PEP to these folks if they haven't had a recent STI but if they feel they are at risk of one because they have multiple sexual partners.
In addition, clinicians can consider doxy-PEP for straight, cisgender men who are at risk of STIs, although there are no studies yet looking at use in this population. Doxy-PEP was not effective in the only study to date conducted in cisgender women so more research is needed before doxy-PEP's use after vaginal sex is recommended.
How do I take Doxy-PEP?
Take a single dose of doxycycline as soon as possible but no more than 72 hours after having condomless sex to reduce the risk of three STIs: syphilis, gonorrhea and chlamydia. Doxy-PEP is usually given as two,100-milligram pills or one 200-milligrams tablet.
Doxycycline should be taken with a glass of water and you should not lie down for 30 minutes after taking the pills.
How well does Doxy-PEP work?
In several studies, doxy-PEP reduced the risk of gonorrhea by about 55-60% and decreased the chances of developing chlamydia and syphilis by about 80% or more.
How can I get Doxy-PEP?
You need a prescription, so speak to a health care provider. You don't have to go to your primary care provider for a prescription, however. There are sexual health clinics that provide medicine to prevent HIV infection before or after sex, STI testing and Mpox vaccination. Many of these clinics also provide doxy-PEP.
How much does Doxy-PEP cost?
Some clinics provide doxy-PEP for free. But even if someone needs to purchase it, it's typically pretty cheap and often covered by insurance.
Does Doxy-PEP have any side effects?
Doxy-PEP can upset your stomach and may make you more sun sensitive, so people who have fair skin or live in a very sunny climate might want to use sunscreen. Occasionally, people can get an allergic reaction or a rash to doxy-PEP.
