Doxy PEP is a single 200mg dose of the antibiotic doxycycline, taken within 72 hours after sex, to reduce the risk of bacterial sexually transmitted infections. The CDC recommends it for gay, bisexual and other men who have sex with men, and for transgender women, who have had a bacterial STI in the past 12 months. A licensed provider can prescribe it through a telehealth visit.
What doxy PEP is
Post-exposure prophylaxis means taking a medication after a possible exposure to reduce the chance of infection taking hold. Doxy PEP applies that idea to three bacterial STIs: syphilis, chlamydia and gonorrhoea.
The regimen is deliberately simple. After oral, vaginal or anal sex, you take 200mg of doxycycline as soon as possible — ideally within 24 hours, and no later than 72 hours. The maximum is 200mg in any 24-hour period, regardless of how many encounters occurred.
Two things doxy PEP does not do: it offers no protection against HIV, and it does not prevent viral STIs such as herpes or HPV. It is one tool within a broader sexual health approach, not a replacement for condoms, HIV PrEP or regular testing.
How well does it work?
This is where the picture has become more nuanced, and it’s worth understanding properly.
The pivotal DoxyPEP trial, published in the New England Journal of Medicine, found roughly a two-thirds reduction in bacterial STI incidence overall among participants, with the strongest effect against chlamydia and syphilis and a more modest effect against gonorrhoea.
Real-world data has largely supported this. A 2025 study across several Kaiser Permanente regions, published in JAMA Internal Medicine, found reductions of around 79% for chlamydia and 80% for syphilis — but only 12% for gonorrhoea. San Francisco, the first major US city to endorse doxy PEP locally, reported roughly 50% drops in both chlamydia and early syphilis cases among the target population after implementation.
Gonorrhoea is the weak point, and it appears to be weakening further. A large Kaiser Permanente Southern California analysis reported in 2026 found overall effectiveness of about 66% against chlamydia and 61% against syphilis, but essentially no measurable protection against gonorrhoea by the end of the study period — down from around 42% early on. The likely explanation is tetracycline resistance in gonorrhoea, which was already common when the original trials ran.
The practical takeaway: doxy PEP is a strong tool against syphilis and chlamydia, and should not be relied on for gonorrhoea prevention. Regular testing still matters.
Who the CDC recommends it for
CDC’s 2024 guidelines are specific. Doxy PEP is recommended for:
- Gay, bisexual and other men who have sex with men, and transgender women
- who have had at least one bacterial STI — syphilis, chlamydia or gonorrhoea — diagnosed in the previous 12 months
The 12-month window is a marker of ongoing exposure risk. A rectal chlamydia diagnosis six months ago qualifies. A single syphilis diagnosis eleven months ago qualifies.
CDC also notes that providers may discuss doxy PEP with people in these groups who haven’t had an STI in the past year but anticipate activity that increases exposure risk, using shared decision-making.
Doxy PEP is not currently recommended for cisgender women or heterosexual men. This isn’t an oversight — a randomised trial in Kenyan cisgender women did not find a reduction in bacterial STIs, and the evidence base in these groups is insufficient to establish a favourable benefit-risk balance. CDC advises providers to use clinical judgement and shared decision-making outside the recommended populations.
Side effects and considerations
Doxycycline is a widely used, generally well-tolerated antibiotic. The common issues:
- Stomach upset and nausea. Taking the dose with food and a full glass of water helps. Don’t lie down immediately afterwards.
- Sun sensitivity. Doxycycline increases susceptibility to sunburn. Use sunscreen and cover up.
- Oesophageal irritation. Take it upright with plenty of water.
Doxy PEP is contraindicated if you’re already taking daily doxycycline or another tetracycline for a different condition. Tell your provider about every medication you take. If you can’t tolerate doxycycline, doxy PEP isn’t an option — no alternative antibiotic has been studied for this use.
The broader concern is antimicrobial resistance. Repeated antibiotic exposure can drive resistance in the target organisms and in other bacteria you carry. The declining effectiveness against gonorrhoea is a live illustration. This is one reason doxy PEP is targeted at populations with demonstrated benefit rather than offered universally, and why ongoing need should be reassessed regularly.
Testing and follow-up
Doxy PEP isn’t a prescription you collect and forget.
CDC guidance is that you should be tested for bacterial STIs when you start, and continue testing every three to six months thereafter — including at genital, oral and anal sites as relevant to your exposures. HIV screening is recommended for HIV-negative people in the recommended groups, according to current screening guidance.
Your provider should also reassess whether you still need doxy PEP every three to six months. Circumstances change, and the resistance considerations above make indefinite use without review a poor idea.
How to get doxy PEP through telehealth
The 72-hour window is what makes speed matter. If you’re waiting a week for an appointment, the medication won’t be in hand when you need it.
A telehealth visit works well here because the evaluation is history-based: a provider needs your STI history, current medications, allergies and exposure context — none of which require a physical examination.
What to have ready:
- Dates and results of any STI diagnoses in the past 12 months
- Your current medications, including any long-term antibiotics
- Any known allergies, particularly to tetracyclines
- Your current HIV status and whether you’re on PrEP
- Your preferred pharmacy
Prescriptions are written to cover anticipated need until your next visit, so you have doses on hand rather than scrambling within the 72-hour window.
At QuickCare365, an STI-related consultation starts at $14.99 and is delivered by a licensed nurse practitioner, with prescriptions sent electronically to the pharmacy you choose. Visits are available 8:00 AM to 11:00 PM, seven days a week.
What happens during the visit
A provider will confirm your eligibility against the CDC criteria, review your medication list for tetracycline interactions, check for allergies and contraindications, and discuss how doxy PEP fits alongside condoms, HIV PrEP and your testing schedule. If it’s appropriate, they’ll send a prescription to your pharmacy and set out a follow-up plan.
If you don’t meet the recommended criteria, expect a conversation rather than an automatic prescription. Shared decision-making outside the recommended groups is explicitly what CDC asks providers to apply, and a provider who prescribes without that discussion isn’t following the guidance.
Information here reflects CDC’s 2024 clinical guidelines. Guidance evolves — your provider will advise on what’s right for your situation.
Talk to a licensed provider about doxy PEP — visits from $14.99.
Frequently asked questions
How quickly do I need to take it?
As soon as possible after sex — ideally within 24 hours, and no later than 72.
Can I keep a supply on hand?
Yes. Prescriptions are written to cover anticipated need, which is the point — the medication only works inside the 72-hour window.
Do I need an STI test before starting?
CDC recommends testing when you start doxy PEP and every three to six months afterwards.
Is the consultation discreet?
Yes. Telehealth visits are protected health information under HIPAA.
Does doxy PEP protect against HIV?
No. It targets bacterial STIs only. Discuss HIV PrEP separately with your provider.
Can I take it if I’m on HIV PrEP?
Many people do — the original trials were largely conducted in people on PrEP or living with HIV. Tell your provider about all medications.
