CNWL

Sexual Health Services
in London and Surrey

Doxy-PEP

We are working hard to bring Doxy-PEP to you directly via our service. In the meantime, we have created this page to provide you with the latest information about Doxy-PEP. If you would like to know more, including where to buy it. Check out Queer Health’s Doxy-PEP guide.

What is Doxy-PEP?

Doxy-PEP (Doxycycline Post-Exposure Prophylaxis) is a pill taken after sex to help prevent sexually transmitted infections (STIs) like chlamydia and syphilis.

You take 200mg of doxycycline (an antibiotic) within 24 hours of having sex, but no later than 72 hours. This can lower the chances of getting certain STIs.

Doxy-PEP only works for bacterial STIs. It won’t protect you from viruses like HIV or hepatitis B. You can find out more information and book an appointment about HIV prevention with PrEP here.

You can take Doxy-PEP as often as you need, but follow these instructions.

How do I take Doxy-PEP?

To use Doxy-PEP:

  • Take 200mg of doxycycline (two 100mg pills) within 24 hours of having sex, but no later than 72 hours.
  • Don’t take more than 200mg (two pills) in a 24-hour period.
  • Take it with a big glass of water and some food to reduce the chance of side effects.
  • Avoid dairy, antacids, and supplements with calcium, magnesium, or iron for two hours before or after your dose, as these can make it less effective.
  • If you have sex again, wait at least 24 hours before taking another dose.

You can take Doxy-PEP as often as you need, but follow these instructions.

How well does Doxy-PEP work?

Studies show that Doxy-PEP can:

  • Lower the chance of getting chlamydia by 70-89%
  • Reduce the risk of syphilis by 73-87%
  • Protect against gonorrhoea by 51-57%

It’s a bit less effective for gonorrhoea because some strains of the bacteria have become resistant to doxycycline. Experts are keeping an eye on this.

Are there any risks or side effects?

Doxycycline is usually safe, but some people might feel mild side effects like nausea, headaches, or stomach upset. You can lower the risk of these by:

  • Taking it with water and food
  • Staying upright (not lying down) for 30 minutes after taking it to avoid acid reflux

Doxycycline can make your skin more sensitive to sunlight, so if you use Doxy-PEP often, wear sunscreen.

Who shouldn’t use Doxy-PEP?

You shouldn’t use Doxy-PEP if:

  • You’re allergic to doxycycline or other antibiotics in the tetracycline family
  • You’re taking certain medications (like acne treatments with vitamin A, certain antibiotics, blood thinners, or epilepsy meds). Check with your doctor if you’re on these.

If you’re pregnant or think you might be, talk to your doctor before using Doxy-PEP.

Antimicrobial Resistance

Antimicrobial resistance happens when bacteria evolve and no longer respond to antibiotics that usually kill them.

Some people worry that using doxycycline regularly might lead to antibiotic resistance or upset the balance of healthy bacteria in your gut. However, many experts believe that this is unlikely to be a significant issue. Doxycycline has been used for long-term treatments for conditions like acne without causing widespread resistance. Ongoing research will help us understand the potential impacts of Doxy-PEP on resistance.

Where can I get Doxy-PEP?

Doxy-PEP is not yet available thought the NHS in the UK.

However, 1 in 9 gay, bisexual and other men who have sex with men are already using Doxy-PEP.

For more details and where to buy it, check out Queer Health’s Doxy-PEP guide.