FAQs
Key Points:
- Doxy-PEP can lower the risk of syphilis and chlamydia, but it isn’t very effective at preventing gonorrhoea.
- Doxy-PEP doesn’t prevent HIV transmission.
- Doxy-PEP may be a good option for people at higher risk of syphilis, such as those who’ve had syphilis or several other STIs in the past year.
- It works by taking 200 mg of doxycycline (usually two tablets) within 72 hours (or up to three days) after sex.
- You shouldn’t take more than one dose within a 72-hour period.
- Even if you use doxy-PEP, it’s still important to get regular sexual health tests.
What is Doxy-PEP?
Doxy-PEP means taking a dose of the antibiotic doxycycline within 72 hours of having sex to reduce your risk of getting syphilis and chlamydia.
Doxy-PEP is short for ‘Doxycycline Post-Exposure Prophylaxis’. Doxycycline is a safe and widely used antibiotic used for a range of conditions. Doxy-PEP does not prevent HIV transmission.
Doxy-PEP has been found to reduce transmission of syphilis by 70-80% and chlamydia by 70-90%. Doxy-PEP is a great option if you’re having lots of sex, or sex with multiple partners in a short window (like on holiday, at a festival, sex party or chemsex).
Who can use doxy-PEP?
Depending on your sex, gender, sexual experiences and STI/BBV risk, your doctor may take an opportunity during an appointment to discuss your suitability for accessing doxy-PEP.
Doxy-PEP is currently recommended for gay and bisexual men, trans women and nonbinary people assigned male at birth who are identified as having an increased risk of being impacted by chlamydia or syphilis.
To access doxy-PEP you need to be making an informed decision with awareness of the benefits and risks. Your doctor will also check that you have no medical or physical reason not to take the medication (these are uncommon but include being pregnant or risk of pregnancy, or have had severe adverse reactions to doxycycline or similar medications previously).
Factors which may make you suitable to use doxy-PEP include:
- Having a recent diagnosis of syphilis, or more than one other bacterial STI within the last 12 months
- Having an upcoming short period of higher risk like a holiday, sex party or chemsex
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- Having multiple sexual partners including both cis males and people with a uterus
Currently there is not enough evidence whether doxy-PEP is effective for transmasculine people, cis women and nonbinary people assigned female at birth, so is not recommended for use by these people.
How do I take doxy-PEP?
Doxy-PEP needs to be taken within 72 hours (3 days) of sexual activity where there’s a possible risk for STI transmission, including oral, anal or vaginal sex.
Your prescription will have instructions about how to take doxy-PEP, which will involve taking a 200mg dose of doxycycline (usually two 100mg pills) within 72 hours after your last sexual contact. It’s important that the medication is taken within the correct timeframe for it to be effective.
If you’re seeking doxy-PEP, be sure to tell your doctor if you are taking any other medications. Doxy-PEP does not interfere with HIV medications (like PrEP and ARTs), and it does not prevent HIV.
Do not take doxy-PEP more than once every 72 hours.
How is Doxy-PEP different to PEP and PrEP for HIV?
Doxy-PEP is different to PEP and PrEP. They are all different kinds of prophylaxes, which just means any steps taken to preserve health or prevent disease. The medications known as PEP and PrEP are used specifically to prevent HIV transmission, whereas doxy-PEP is used to prevent chlamydia and syphilis – doxy-PEP does not prevent HIV.
It might feel confusing, but we are grateful that different options are becoming available to maintain our sexual health and be proactive to keep ourselves and our partners safer.
Where can I get doxy-PEP?
Doxy-PEP can only be purchased from a chemist or pharmacy with a prescription from a doctor. You can ask your regular GP or a sexual health clinician about getting a prescription, and they will talk to you about your sexual behaviours and personal risk factors to decide if doxy-PEP is suitable for you. You can then access the doxy-PEP ahead of any upcoming sexual contact and have it ready to go when you need it. Not all doctors will know about doxy-PEP, if you think it's right for you, you can show a doctor this Doxy-PEP Decision Making Tool.
Your prescription will provide more than the two pills needed for one dose of Doxy-PEP. It’s important to be aware of the risk factors and only it take it when necessary (never more than once within 72 hours). Like other antibiotics, taking doxy-PEP is not suitable for everyone, and taking it too frequently can contribute to antibiotic resistance.
Do I still need to use condoms and other safer sex methods?
Yes. Doxy-PEP is intended for infrequent or occasional use, so it’s important to take other steps to maintain your sexual health.
Even if you use doxy-PEP, you should also have regular testing for STIs because doxy-PEP only works to prevent chlamydia and syphilis and is effective around 80% of the time.
Doxy-PEP is not effective to prevent transmission of gonorrhoea, and also does not help to prevent viral infections including HIV or herpes. For more coverage, consider using additional protection during sex, including barrier methods like condoms and taking PrEP.
Doxy-PEP does not interact with HIV PrEP and PEP or HIV antiretroviral therapies (ARVs/ARTs) so it’s ok to take doxy-PEP if you’re also using any of these medications.
Syphilis and chlamydia are both very treatable infections, especially when they’re detected early. So, you don’t have to take doxy-PEP if there are other safer sex practises that suit you better - some people are comfortable having frequent STI testing and using condoms.
What are the side-effects of doxy-PEP?
Doxy-PEP side effects are typically mild and not common. They may include nausea, vomiting, diarrhoea and reflux, as well as sun-sensitivity.
Doxy-PEP side effects can be reduced by taking the medication with food and plenty of water and avoiding lying down in the hour after taking it, which helps prevent it irritating your throat and stomach. You should also use sunscreen and other sun protection when outside while you’re taking Doxy-PEP.
Doxy-PEP can interfere with other medications (though it does not interfere with PrEP and ARTs) so it’s important to disclose any other medications you’re using to your doctor. Some supplements (including zinc, calcium, iron and fibre, as well as antacids) can interfere with your body absorbing the medication so should not be taken within 2 hours of taking doxy-PEP.
More Information
Doxy-PEP: Doxycycline STI prevention for gay and bi+ guys in Australia | Emen8
Doxy-PEP (doxycycline post-exposure prophylaxis): Should I take antibiotics to prevent STIs?