27 November 23

Ending HIV

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

While PrEP has been helping us tremendously with preventing new HIV transmissions, STIs continue to be a relatively common occurrence in many guys’ sex lives.

This is why our newest tool, Doxy-PEP, the use of antibiotic doxycycline taken to prevent STI transmission, is so exciting. ASHM (Australia’s peak body for HIV, blood-borne viruses (BBVs), and sexual and reproductive health) has now listed Doxy-PEP as an option for guys who are most at risk of STI transmission.

What is Doxy-PEP?

Doxy-PEP is the use of the antibiotic doxycycline after sex to reduce the risk of transmitting bacterial STIs, such as syphilis, chlamydia and, to a much lesser extent gonorrhoea. 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%). Meanwhile, it was less effective in preventing gonorrhoea, proving ineffective in some trials or with only a 50–55% reduction in other trials. This is believed to be caused by varying levels of antibiotic-resistant gonorrhoea amongst the trial participants.

How does it work?

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

In general, ASHM has not recommended using doxycycline more frequently than this, which otherwise might be thought of as ‘Doxy-PrEP’ (taking 100mg daily). It may, however, be appropriate for guys during periods of heightened (daily) sexual activity that put them at risk of STIs. As we don’t yet have a clear idea of its efficacy for its use in this way, it is a decision between you and your doctor.

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.

However, you should avoid taking Doxy-PEP within 2 hours of multivitamins, fibre or other supplements as they may reduce the absorption in your stomach, making the medication less effective.

Who is Doxy-PEP for?

Doxy-PEP has only been recommended for gay, bisexual and other men who have sex with men who are at the highest risk of STIs and only for use over a short duration. This is to limit the risk of any associated antibiotic resistance and any potential disruptions to the person’s gut microbiome.

While clinical guidelines are yet to be released, the ASHM consensus statement included potential eligibility criteria for gay, bisexual and other men who have sex with men who:

• • has had a syphilis diagnosis within the past six or 12 months
  • has had two or more STI diagnoses that aren’t syphilis within the past six or 12 months
  • is about to have a period of heightened STI risk, for example, attendance at a sex event or holiday plans that likely involve sexual activity with multiple casual sexual partners
  • has concurrent male and cis female sexual partners or other sexual partners that have a uterus

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. 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 may now be possible to access Doxy-PEP with a doctor (GP) if you are interested in getting it. With guidance provided by ASHM on how to provide it safely, some GPs and sexual health doctors may soon start to offer Doxy-PEP scripts in conjunction with regular HIV and STI testing.

However, it is early days in the process, and while we are still waiting for official clinical guidelines for Doxy-PEP, many doctors may be reluctant to prescribe it, even if you believe you meet the above eligibility criteria. The good news is that ASHM is currently in the process of developing such guidelines, along with education and other resources for doctors – so we’ll need to wait a little longer for this to take place!