Doxycycline postexposure prophylaxis (doxyPEP) is a method of reducing transmission rates of certain bacterial sexually transmitted infections (STIs). It involves taking an oral dose of doxycycline, an antibiotic, soon after having sex without a barrier method.
Doxycycline comes as a generic drug, and it may also be available under brand names like Acticlate or Monodox.
DoxyPEP is currently only recommended for certain groups, including transgender women and males who have sex with males. Talk with your doctor about your options for preventing STIs.
Healthcare professionals can prescribe doxyPEP to help prevent gonorrhea, chlamydia, and syphilis, which are bacterial STIs. The medication is meant to be taken within 3 days of having vaginal, anal, or oral sex without a barrier method.
Studies included in a 2025 research review note that doxyPEP may help lower transmission of gonorrhea by around 33% to 50% and syphilis and chlamydia by more than 70%. It may be less effective for gonorrhea due to the number of doxycycline-resistant strains.
Reducing transmission of these STIs is important, as they can lead to severe complications like fertility loss, organ damage, and increased HIV risk.
What doxyPEP doesn’t do
Doxycycline is an antibiotic, meaning it can only help prevent bacterial infections — and current evidence only supports its use in preventing gonorrhea, chlamydia, and syphilis.
It can’t prevent viral infections like HIV, but you can take it at the same time as postexposure prophylaxis (PEP) for HIV.
Currently, doxyPEP is recommended for:
- transgender women
- gay, bisexual, and other people assigned male at birth who have sex with people assigned male at birth
Studies have shown that doxyPEP can be effective at preventing bacterial STIs in these populations. Healthcare professionals may discuss doxyPEP with people who fall into these categories and have a history of gonorrhea, chlamydia, or syphilis in the past 12 months.
Though other people may also benefit from doxyPEP, such as cisgender females, more studies are needed to demonstrate its effectiveness. Future doxyPEP recommendations may eventually include other groups.
If you don’t fall into one of these groups, talk with your doctor about your options.
They may still recommend doxyPEP, or they may suggest another treatment method. For example, people who have sex with people of a different assigned sex at birth may be able to receive expedited partner therapy for gonorrhea or chlamydia.
You may be able to get a doxyPEP prescription from several types of healthcare professionals who are licensed to prescribe medications, including primary care doctors and nurse practitioners. Rules around who can or can’t prescribe medications may vary by state, so it may be best to check your state’s regulations first.
Additionally, local health departments or clinics like Planned Parenthood may be able to prescribe doxyPEP. Some places may require in-person appointments, or they may offer telehealth services.
The cost of doxyPEP can vary depending on a few factors, including where you live, whether you have insurance, and whether your insurance plan covers it. Planned Parenthood notes that one dose of doxycycline may cost anywhere from $0 to $35, depending on your insurance.
Many insurance plans partially or fully cover doxyPEP. If you have insurance and want to find out more about the cost, contact your insurance company.
Doxycycline is an oral medication, meaning it comes as a tablet or capsule that you take by mouth. You’ll receive either one pill containing 200 milligrams (mg) of doxycycline or two pills containing 100 mg of doxycycline each.
Take the pill with plenty of water up to 72 hours (3 days) after oral, anal, or vaginal sex without a barrier method. Though doxyPEP can be taken daily, don’t take more than 200 mg in a 24-hour period.
Your healthcare professional may then recommend STI testing every 3 to 6 months.
Tips for taking doxyPEP
DoxyPEP may cause side effects like nausea if taken on an empty stomach, so try taking it with food. It may also make your skin more sensitive to the sun, so wear sunscreen after taking it and reapply often.
Also, don’t take doxyPEP within 2 hours of consuming:
- antacids
- supplements that contain calcium
- dairy products
These may reduce the effectiveness of doxyPEP.
DoxyPEP involves taking oral doxycycline within 3 days of having oral, anal, or vaginal sex without a barrier method. It can help reduce transmission rates of gonorrhea, chlamydia, and syphilis.
Remember that even with doxyPEP, it’s still important to take additional measures to protect yourself against STIs. Use barrier methods correctly and every time, and consider regular STI screenings.