What is Doxy-PEP and how does it prevent STIs?

Doxy-PEP is used after unprotected condomless sex to prevent syphilis, chlamydia, and gonorrhea for MSM and trans women. Partner with a clinician to see if doxy-PEP makes sense for your sexual health regimen.

October 27, 2023
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  • Doxy-PEP is used for: preventing gonorrhea, chlamydia, and syphilis infections (bacterial STIs).
  • It can drastically reduce the risk of gonorrhea, syphilis and chlamydia among transwomen and gay, bisexual and other men who have sex with men.
  • When taken 24-72 hours after unprotected sex, STI rates are significantly reduced in this population.

If you’ve been around the sexual block, you may have heard of PrEP for HIV, and even PEP for HIV; but have you heard of doxy-PEP? Doxy-PEP, short for doxycycline post-exposure prophylaxis, is a new treatment shown to lower the risk of the three most common bacterial STIs (syphilis, gonorrhea, and chlamydia). Learn if it may be beneficial for your sex life, how take it, and how to get doxy-PEP.

Is doxy-PEP right for me?

Sexually transmitted infections, or STIs, are on the rise. As a new STI prevention treatment, doxy-PEP is available for preventing significant infections with syphilis, gonorrhea, and chlamydia in cisgender gay and bisexual men and transgender women. If you’ve had a lot of unprotected sex, including anal, oral, and vaginal sex, doxy-PEP may be a good option.

Per the CDC, doxy-PEP is currently only recommended in gay and bisexual men, and transgender women. If you fall into one of these LGBTQIA+ groups, and have had one of the three major bacterial STIs in the last year (syphilis, gonorrhea, or chlamydia), you may be at a higher risk for STIs. Having multiple sex partners, taking PrEP, or living with HIV, are considered additional STI risk factors.

You’ll want to talk with your health care provider about all of your STI risk factors. Then, you and your clinician can decide whether doxy-PEP makes sense for your sexual health regimen.

What is doxycycline?

Doxycycline is a common antibiotic used to treat skin, respiratory, and dental infections. Doxycycline is also used to treat acne, malaria, and MRSA (methicillin-resistant Staphylococcus aureus). It belongs to the drug class of medications called tetracyclines.

It is a relatively inexpensive medication and is often covered by insurance. You will need a prescription from a healthcare provider to take it.

How do I take doxy-PEP?

For best results, take 200mg of doxycycline hyclate long-acting within 24 to 72 hours after condomless or unprotected sex. You will want to take it once within the 24 to 72-hour time frame.

The CDC recommended screening for STIs every three months while taking doxy-PEP. If you’re at risk for HIV, routine HIV testing should be done. Additionally, annual blood tests are recommended for monitoring for any harmful effects of antibiotics, including CBC, liver, and kidney tests.

What are the benefits of doxycycline as PEP?

Doxycycline is generally a safe, affordable, and well-tolerated medication. The most common side effects are stomach upset (diarrhea) and sun sensitivity (photosensitivity). If you do take doxy-PEP, be sure to wear extra protection like layers and sunscreen if you live in a sunny area. You can also take doxy-PEP with food to avoid an upset stomach.

How do I get doxy-PEP?

Partner with your clinician to decide about taking doxy-PEP. First, make an appointment with your clinician, and discuss your sexual health history. Being open about what kinds of sex you have, how many partners you have, and if you’ve had an STI in the last year is important information to share. Know that our clinicians will never judge you, and are open to talking about all kinds of sex. It’s important to make an appointment with a trusted healthcare professional, like your primary care provider, before getting a prescription.

Can doxy-PEP curb rising STI rates?

For common bacterial STIs (the big three-chlamydia, syphilis, and gonorrhea), STI rates increased from 2.4 million in 2020 to 2.5 million in 2021. Curbing rising STI rates by getting tested and treated is key to preventing infection in high-risk groups.

We see consistent benefits when doxy-PEP is used to prevent these STIs in gay and bisexual men and transgender women having anal and oral sex. The verdict is out on how effective doxy-PEP is for cis women having vaginal sex. A recent study suggests doxy-PEP may be less useful in reducing STIs in this population.

For men who have sex with men, STI rates have been steadily increasing for decades. For women, STIs have also been increasing, notably syphilis. It’s important to know if you’re in a high-risk group. Examples of high-risk sexual activities include unprotected sex with multiple sex partners; anal sex with a partner whose HIV and STI status is unknown and having sex without a condom; and mixing heavy substance use and sexual activities. Additionally, research demonstrates that if you’ve had an STI in the last twelve months, you are at a higher risk of contracting an STI. There’s nothing wrong with that! STIs are common, and many respond well to treatment.  It’s just important to be aware of your risk factors, so you can make the best choices for your health and sex life.

What about antibiotic resistance?

Benefits so far seem to outweigh the risks when it comes to doxy-PEP. Because bacterial STIs are treated with antibiotics, taking doxy-PEP has been shown to reduce the use of broader spectrum antibiotics, like ceftriaxone, by 50%, according to Annie Luetkemeyer, MD, professor of infectious diseases at Zuckerberg San Francisco General Hospital and UCSF. Either way, you need antibiotics to treat these three STIs. Doxy-PEP might reduce future issues with resistance and the use of other antibiotics.

Resistance to antibiotics is becoming a bigger problem for all kinds of infections. When resistance develops, it becomes harder to treat infections with medications we know have previously worked. There are two concerns about resistance with doxy-PEP. Will doxy-PEP work less effectively for those who have already taken doxycycline for treatment of previous gonorrhea infections? Will more widespread use of doxy-PEP as prophylaxis increase resistance to doxycycline for community cases of staph aureus skin infections? 

So far, there does not seem to be a major increase in resistance to methicillin-resistant staph aureas (MRSA) which is promising. Still, it will be important to monitor how doxy-PEP affects antibiotic resistance over time. Additionally, future studies will also look at how doxy-PEP impacts the gut microbiome and metabolic health over time. [Source: Doxycycline Postexposure Prophylaxis and Sexually Transmitted Infections - JAMA Insights “Ultimately, antimicrobial drug resistance monitoring is needed to understand if doxy-PEP use increases the risk for drug-resistant microbes.”]

How is doxy-PEP different from HIV PEP?

How is doxy-PEP different from HIV PEP? HIV PEP (post-exposure prophylaxis) is an antiretroviral to prevent HIV viral infections. Doxy-PEP is an antibiotic used to prevent three different bacterial infections. Both are post-exposure STI prevention medications. Know that if you take HIV PrEP, or HIV PEP, you can still take doxy-PEP.

Doxy-PEP has been studied to reduce your likelihood of contracting syphilis, chlamydia, or gonorrhea. Doxy-PEP does not provide protection against viral STIs like HIV, herpes, or HPV. You can still decide to rely on other methods to reduce your risk of STIs. Using any barrier method, such as internal or external condoms, along with dental dams, can reduce fluids and STI transmission. Using fingers and toys also can reduce transmission–but be sure to clean those before and after sex! Some people like to ask a new partner to get tested, and get tested themselves, before entering into a new sexual relationship, especially if you are not wanting to use condoms. Consider your expectations and the measures you decide to take when it comes to STIs.

We understand there is often stigma surrounding STIs, especially with folks who don’t have access to sexual health care. Infections that occur without any symptoms (asymptomatic) are common and undertreated in communities where people are reluctant to get sexual health care. At FOLX, our clinicians and care team are here to talk through all aspects of sexual health with you. Your sex life and sexual well-being matter. We want you to be aware of any sexual health risks and partner with you to take steps to keep you safe and healthy.

Doxy-PEP has been studied to reduce your likelihood of contracting syphilis, chlamydia, or gonorrhea. Always consult with a healthcare professional before taking any medication or if you believe you may have been exposed to an STI. FOLX can help if you have any questions about an exposure or about if Doxy-PEP is right for you! Our clinicians are happy to write you a prescription, and partner with you to make the best decisions for your sexual well-being.


FOLX Health is the first digital healthcare company designed by and for the LGBTQIA+ community. Our services include virtual primary care, gender-affirming hormone therapy including estrogen and testosterone (HRT), mental health care, sexual and reproductive health care, preventive care, and fertility consultations. FOLX memberships give you access to LGBTQIA+ expert clinicians, peer support, thousands of LGBTQIA+ resources, and more. Whether you’re lesbian, gay, bisexual, transgender, queer, gender non-conforming, or nonbinary, you can find LGBTQIA+-specialized health care that helps you meet your wellness goals. FOLX Health is health care that's queer all year. Get all the benefits of becoming a FOLX member and sign up today!