Bacterial sexually transmitted infections (STIs), such as gonorrhea, chlamydia, and syphilis, are increasing across the United States. In June 2024, the CDC announced new recommendations for a novel approach to combat this rise by using doxycycline as post-exposure prophylaxis (PEP). You may be familiar with using PEP to prevent viral infections like HIV or pregnancy, but this represents a new public health strategy for bacterial infection prevention.
Who does the CDC recommend doxycycline PEP for?
STIs like syphilis, chlamydia, and gonorrhea disproportionately affect gay, bisexual, and other men who have sex with men (MSM) and transgender women (TGW). The CDC recommends doxycycline PEP for MSM and TGW who have had a bacterial STI in the past 12 months and have had condomless oral, vaginal, or anal sex within the last 72 hours. In urgent care, this could apply to a patient who presents for an STI check or mentions a recent high-risk exposure but is not symptomatic. The treatment consists of a one-time dose of 200 mg of oral doxycycline.
How effective is this strategy in preventing bacterial STIs?
Randomized controlled trials have demonstrated that this strategy reduces the contraction of syphilis and chlamydia infections by over 70% and gonococcal infections by about 50%.
Can it be used in other populations?
Although pharmacokinetics suggest it could be effective in other populations (such as cisgender women, cisgender heterosexual men, and transgender men), it’s a matter of shared decision-making with the patient, as these populations are not at the highest risk.
What side effects do I need to know?
The main side effects include gastrointestinal symptoms and photosensitivity. It’s also important to remind patients to take it with water to avoid pill esophagitis.
What about antibiotic stewardship—will this increase resistance?
Expert consensus at this time is that the benefits outweigh the risks from a public health standpoint, and preventing infections in your patient will also help prevent infections downstream. It's important to note that this isn't truly a choice between using antibiotics or not, as patients who develop bacterial STIs would require antibiotics anyway. There’s no long-term data on how this might affect the microbiome, but doxycycline has been used for many years and still an effective antibiotic.
What’s the bottom line?
Doxycycline PEP (200 mg once) taken after condomless intercourse is recommended for bacterial STI prevention in high-risk populations.
I plan to offer doxycycline PEP to my high-risk patients who come to urgent care or the emergency department for an STI-related concern. Check out the Doxy-PEP episode of Urgent Care Reviews and Perspectives, where Andy Little, DO, and I discuss this new strategy in detail!
