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The UK’s first national clinical guideline on the use of doxycycline post-exposure prophylaxis (doxyPEP) has been published by the British Association for Sexual Health and HIV (BASHH).
The guidance, published on 9 June 2025, makes the UK one of the first countries in the world to “offer formal clinical direction on this STI prevention strategy”, BASHH said.
It recommends doxyPEP for gay and bisexual men who have sex with men and transgender women, owing to an “elevated risk” of acquiring syphilis.
“Clinicians may consider doxyPEP for people assigned female at birth at elevated risk of acquiring syphilis, on a case-by-case basis and in discussion with the patient,” the guidance said.
It recommends taking “a single dose of 200mg (i.e. 2 x 100mg capsules) of doxycycline within 24 hours and no later than 72 hours after sex”.
The guidance cites studies that found a reduction in syphilis cases in patients who received doxyPEP, with the results of one study, published in March 2025, showing an 80% reduction in cases.
Latest data from the UK Health Security Agency (UKHSA), published on 3 June 2025, show that syphilis cases increased by 5% in 2024 compared with 2023.
Cases of syphilis, including late-stage syphilis or complications from the infection, increased from 12,456 cases in 2023 to 13,030 cases in 2024, according to the data.
BASHH said that 2024 had the highest recorded number of cases since 1948.
Matt Phillips, president of BASHH, said: “We want to ensure that those at highest risk of serious STIs, such as syphilis, can benefit from evidence-based prevention strategies, such as doxyPEP. The development of the doxyPEP guidelines has been an exemplar of stakeholder engagement and collaboration across a range of disciplines, ensuring the guidance is balanced, expert-led and reflective of the real-world needs of patients and clinicians.
“With clear clinical guidelines now in place, we look forward to seeing the impact of its application, supporting improved sexual health outcomes and helping to ease pressure on sexual health services.”
John Saunders, deputy head of programme delivery and service improvement for blood safety, hepatitis, STI, and HIV division at UKHSA, said: “As one of the first countries in the world to issue a formal guideline on the use of doxyPEP, the UK is taking a bold step forward in addressing the continuing rise in syphilis cases.
“This simple intervention has the potential to drastically reduce cases, lowering infection risk by 77%, and protect those at greatest risk from serious and irreversible harm.”
Commenting on the guidelines, Nathan Burley, advanced public health/sexual health services pharmacist at NHS Greater Glasgow and Clyde, said: “The publication of the new doxyPEP guideline is a huge step forward for preventative medicine and sexual health.
“Moving the focus away from reactive treatment, doxycycline given post-exposure has been shown to be very effective against acquiring chlamydia and importantly syphilis. Pharmacists in the area have already been right through the middle of this – myself included – helping to ensure this guideline has a smooth landing into practice for our medical, nursing and health advising colleagues to deliver doxyPEP safely and effectively.
“Community pharmacy in particular could be an outlet for patients to receive doxyPEP similarly to how the morning after pill is given out, which is incredibly exciting.”
