DoxyPEP
Doxycycline post-exposure prophylaxis, known as doxyPEP, is an antibiotic that you take after having sex. It can be used to reduce the risk of STIs like syphilis. But it does not work against all STIs.
In the UK, doxyPEP can be prescribed to prevent syphilis. This follows guidelines from The British Association for Sexual Health and HIV (BASHH).
Who can take doxyPEP?
DoxyPEP is recommended for people at higher risk of syphilis, including:
men who have sex with men
trans women
DoxyPEP has not been proven to work for cisgender women, trans men, and other people assigned female at birth. So far, only one research study has been conducted with women, so it’s not commonly recommended. However, if you have an increased chance of syphilis it can be prescribed.
How can I get doxyPEP?
To be prescribed doxyPEP, ask about it at your next visit to a sexual health clinic.
If you are eligible, you can get doxyPEP free from the NHS.
How to take doxyPEP
DoxyPEP is simple to use - take a dose of doxycycline as soon as you can after sex. A dose is 200mg. This usually means taking 2 tablets. Follow the instructions on your medication pack to be sure how many tablets to take.
DoxyPEP is most effective if you take it within 24 hours of sex, but you can take it up to 72 hours afterwards.
Only take 1 dose per day. Do not take more than 200mg of doxycycline in 24 hours. Take the tablets with food and a glass of water.
DoxyPEP is not a daily medication like PrEP. You only take it after condomless sex or when you think there’s been a risk of syphilis.
One dose of doxyPEP can cover all the sex you’ve had in the previous 72 hours (3 days). So if you have sex more than once in that time, you don’t need to take doxyPEP after every time.
DoxyPEP and antibiotic resistance
There are concerns that using doxyPEP could contribute to antibiotic resistance in STIs and other infections.
Antibiotic resistance occurs when bacteria evolves so it cannot be killed by a specific antibiotic. This means the medication no longer works well and the infection has become resistant. This can make infections harder to treat.
Some infections have become resistant to many antibiotics. For example, gonorrhoea is already resistant to tetracycline-style antibiotics, like doxycycline.
Overuse of antibiotics is a known cause of bacteria developing resistance.
At present, there is no clear evidence that doxyPEP is increasing antibiotic resistance. However, it may have some impact, although the extent is not yet understood. Monitoring and research are ongoing.
Concerns about antibiotic resistance should not stop you from taking doxyPEP if you need it. If you're at a higher risk of syphilis, the benefits outweigh the potential risks.
Risks and side effects of doxyPEP
Doxycycline, the antibiotic used for doxyPEP, is very safe to take. It’s used as treatment for many different infections, including chlamydia.
Some people can experience some mild and temporary side effects. This could include nausea, upset stomach or headache.
It can also make your skin more sensitive to the sun. Avoid using sunbeds when taking doxyPEP. On sunny days or when you’re spending time in the sun, protect your skin by covering up, using sunscreen and staying in the shade.
Taking antibiotics, like doxycycline, can affect the balance of bacteria in our gut microbiome. There is yet not enough evidence to know exactly how the microbiome is affected by taking doxyPEP, more research is needed on this.
Having a healthy diet and lifestyle can all contribute to keeping your gut microbiome healthy.
What does it prevent?
DoxyPEP is recommended for reducing the risk of syphilis.
It does not reduce the risk of gonorrhoea or viral STIs like HIV, hepatitis B and C, HPV and HSV. So consider using doxyPEP with other safer sex practices, like condoms, PrEP and vaccinations.
If you’re taking doxyPEP, you should still test regularly for other STIs and speak to your partners about testing.
Do you need help with something else?
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