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Read about the different types of sexual health conditions including sexually transmitted infections (STIs), HIV and AIDS. You can also get information on contraception and abortion.

DoxyPEP (Doxycycline Post-Exposure Prophylaxis)

DoxyPEP is a way of reducing the risk of some sexually transmitted infections (STIs) after sex. It involves taking a dose of the antibiotic doxycycline as soon as possible after sex where there may have been a risk of STI exposure.

DoxyPEP does not protect against HIV. If you are concerned about HIV, you may want to find out more about PrEP (Pre-Exposure Prophylaxis) and PEP (Post-Exposure Prophylaxis for HIV).

What is DoxyPEP?

DoxyPEP (Doxycycline Post-Exposure Prophylaxis) involves taking a single dose of the antibiotic doxycycline after sex to reduce the risk of some bacterial STIs.

Research has shown that DoxyPEP can reduce the risk of getting STIs like:

  • Syphilis
  • Chlamydia

DoxyPEP is not suitable or recommended for everyone. It may be offered to people who are at higher risk of certain bacterial STIs following an assessment by a sexual health professional.

How does DoxyPEP work?

Doxycycline is an antibiotic that can prevent some bacterial infections from becoming established in the body if taken soon after exposure.

To be effective, DoxyPEP should be taken as soon as possible after sex, ideally within 24 hours and no later than 72 hours after exposure. Your clinician will advise you on when and how to take it.

Do I need DoxyPEP?

DoxyPEP is not routinely recommended for everyone.

A sexual health professional may discuss DoxyPEP with you if:

  • You have had recent bacterial STIs
  • You have ongoing sexual health risks
  • You are part of a group shown to benefit from DoxyPEP in clinical studies
  • You would benefit from additional STI prevention alongside other sexual health interventions

The decision to use DoxyPEP should be made with a clinician who can discuss the benefits, risks and any potential side effects.

How do you take DoxyPEP?

DoxyPEP is usually taken after sex where there has been a potential exposure to STIs.

A sexual health professional will explain:

  • The correct dose
  • When to take it
  • How often it can be used safely
  • Any precautions specific to your health or medicines

Always follow the advice of your sexual health service.

Will I have to pay?

No. If DoxyPEP is offered by an NHS sexual health service, it is provided free of charge.

Availability may vary between services and areas.

Can I have sex when taking DoxyPEP?

Yes. DoxyPEP is designed to be used after sex to reduce the risk of certain bacterial STIs.

However, DoxyPEP does not eliminate the risk of infection and should be considered as part of a wider sexual health strategy, which may include:

  • Regular STI testing
  • Condom use
  • HIV prevention (PrEP or PEP where appropriate)
  • Vaccinations, such as hepatitis A, hepatitis B, mpox and gonorrhoea vaccination where eligible

What is the difference between DoxyPEP and PrEP?

DoxyPEP helps reduce the risk of some bacterial STIs after exposure.

PrEP (Pre-Exposure Prophylaxis) helps prevent HIV before exposure.

They protect against different infections and work in different ways. Some people may use both DoxyPEP and PrEP following advice from a sexual health professional.

I'm already taking PrEP. Should I consider DoxyPEP?

Possibly. PrEP is highly effective at preventing HIV, but it does not protect against  other STIs.

If you are taking PrEP and are experiencing recurrent bacterial STIs, your sexual health clinician may discuss whether DoxyPEP could be suitable for you.

Does DoxyPEP protect against all STIs?

No.

DoxyPEP can reduce the risk of:

  • Chlamydia
  • Syphilis

DoxyPEP does not protect against:

  • HIV
  • Herpes
  • Genital warts (HPV)
  • Mpox
  • Hepatitis A, B or C
  • Other infections not affected by doxycycline

Regular STI testing remains important, even if you are using DoxyPEP as it is not 100% effective and doesn’t protect against all STIs.

Are there any side effects?

Like all medicines, doxycycline can cause side effects. Common side effects include:

  • Feeling sick (nausea)
  • Heartburn or indigestion
  • Stomach upset
  • Sensitivity to sunlight (sunburn more easily)

Most side effects are mild and temporary. Your clinician will discuss whether DoxyPEP is appropriate for you and how to reduce the risk of side effects.

Where can I get more information?

Speak to your local sexual health service if you think DoxyPEP may be right for you.

For the latest clinical information, see:

Important: DoxyPEP is a relatively new prevention approach. Availability and eligibility criteria may vary between sexual health services. Speak to a healthcare professional for personalised advice.

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