08 October 24

Ending HIV

Here’s what you need to know about Doxy-PEP

Update: NSW Health has endorsed Doxy-PEP and published a decision aid to assist your discussion on whether to start Doxy-PEP, with your doctor. Find the decision aid available here, and up-to-date information about accessing Doxy-PEP in the article below.

PrEP has been a tremendous tool for preventing new HIV transmissions, however, sexually transmitted infections (STIs) continue to be a relatively common occurrence in many guys’ sex lives.

While condoms remain a tried and tested way of preventing STIs, Doxy-PEP may now also be able to assist in reducing STI transmissions.

Doxy-PEP is the use of antibiotic doxycycline taken to prevent STI transmission. As more people are taking it up in NSW you might be starting to hear a bit about it – so let us get you acquainted!

What is Doxy-PEP?

Doxy-PEP is the use of the antibiotic doxycycline after sex to protect against STIs, specifically syphilis and chlamydia.

Doxycycline is also used to treat a range of bacterial infections, including STIs and is even prescribed to prevent malaria transmission and treat acne at different doses.

Research has shown that using Doxy-PEP is highly effective at preventing certain STIs among gay, bisexual, and other men who have sex with men.

Clinical trials of Doxy-PEP have shown significant reductions in syphilis (by 70–80%) and chlamydia (by 70–90%). However, due to antibiotic resistance, it’s unlikely to protect against gonorrhoea, which is why it’s important to maintain regular STI check-ups every three months.

In September 2023, ASHM (Australia’s peak body for HIV, blood-borne viruses (BBVs), and sexual and reproductive health) listed Doxy-PEP as an option for guys who are most at risk of STI transmission.

As of September 2024, NSW Health has created a decision aid to guide your discussion with your doctor (GP) and formally made a pathway for people at risk of STIs to access Doxy-PEP.

How do I take Doxy-PEP?

To use Doxy-PEP, you take 200 mg of doxycycline (usually two tablets) up to 72 hours after sex to reduce your risk of bacterial STIs. So, if you have multiple encounters over the weekend, a single dose of Doxy-PEP (as described above) is sufficient to help prevent transmission.

Here’s a visual example of how it could work:

Other tips for taking Doxy-PEP

• Take Doxy-PEP in a full glass of water to prevent stomach upset
• Avoid lying down for at least an hour after swallowing the tablets to avoid irritating your food pipe
• Do not take antacids, iron, calcium, zinc or fibre supplements within 2 hours of doxycycline as they may interfere with its absorption
• Apply sunscreen when out in the sun to avoid sunburn
• Do not take Doxy-PEP more than once every three days

It’s not recommended to take doxycycline more frequently than once every three days, which otherwise might be thought of as ‘Doxy-PrEP’ (taking 100 mg daily).

While an argument can be made for its use among guys during periods of heightened (daily) sexual activity, we don’t yet have a clear idea of its efficacy for use in this way. So we’d recommend including this in your discussion with your doctor if this is something you’re looking to do.

Is Doxy-PEP safe to take at the same time as PrEP for HIV?

Yes, it’s safe to take PrEP at the same time as Doxy-PEP; in fact, all participants of the Doxy-PEP trials that led to this development were either taking HIV PrEP or HIV treatment.

Who is Doxy-PEP for?

Doxy-PEP has been recommended for gay, bisexual, and other men who have sex with men and trans women, especially with recent syphilis or multiple recent STIs. It can however be prescribed to anyone who wishes to reduce their risk of syphilis and chlamydia and understands the associated risks and benefits.

Doxy-PEP and antimicrobial resistance

As our collective use of antibiotics to treat a whole host of illnesses continues, there have been concerns raised about the rise of antimicrobial-resistant (also known as antibiotic-resistant) bacteria across the world.

Antimicrobial resistance can mean certain antibiotic treatments are rendered ineffective in treating STIs or other types of bacterial infections, which can have serious consequences for individuals and the broader public health response.

For STIs, this is an issue for gonorrhoea. Widespread use of Doxy-PEP may increase resistant gonorrhoea strains in the community. It is important to weigh these concerns against the benefits of Doxy-PEP, particularly in preventing the serious health complications associated with syphilis.

With this in mind, it’s important that any use of Doxy-PEP needs to be monitored carefully, which can be done by accessing it through a doctor who prescribes Doxy-PEP and not by using pills that have been acquired through other means or intended for other treatment.

There have been reports of people already using doxycycline as Doxy-PEP from left-over medication and using other forms of antibiotics to try and achieve a similar effect. While it’s great to see guys are motivated to try new STI prevention methods, it’s important to access Doxy-PEP in conjunction with your doctor to make sure it’s being taken safely and effectively, and ASHM advises against using other antibiotics to prevent STIs.

How can I get Doxy-PEP?

While Doxy-PEP may not be the right option for everyone, it is now possible to access it with a doctor (GP) if you want to. Be sure to read through NSW Health Doxy-PEP decision aid, and when you are ready to book an appointment with your GP. On the day you can share it with them to assist you in your discussion and help you decide whether Doxy-PEP is a good fit for your circumstances.