Doxycycline Post-Exposure Prophylaxis (Doxy-PEP) is a new strategy for preventing certain sexually transmitted infections (STIs). This approach uses the antibiotic doxycycline to reduce the risk of acquiring a bacterial STI after a potential exposure, interrupting the infection process before it establishes itself. Doxy-PEP has been integrated into public health guidance as a patient-managed biomedical tool for managing rising rates of syphilis, chlamydia, and gonorrhea. It is a prescription medication used only following potential exposure, distinguishing it from daily regimens like HIV pre-exposure prophylaxis (PrEP).
Who Should Consider Doxy-PEP?
Current medical guidelines recommend discussing Doxy-PEP only with individuals who meet specific criteria indicating a high risk of acquiring bacterial STIs. The primary population is gay, bisexual, and other men who have sex with men (MSM) and transgender women (TGW) who have had a bacterial STI diagnosis—specifically syphilis, chlamydia, or gonorrhea—within the past 12 months. This focus is based on strong efficacy data collected from randomized controlled trials within this population.
For people who do not have a recent STI history but participate in sexual activities that increase the likelihood of exposure, providers may still offer counseling and prescribe Doxy-PEP through shared decision-making. This intervention is not recommended for the general population or for low-risk exposure, as there is insufficient evidence to assess the balance of benefits and harms in other groups, such as cisgender women or heterosexual men. The decision to pursue Doxy-PEP should be made in consultation with a healthcare provider who can evaluate individual risk factors.
Securing a Prescription
Obtaining Doxy-PEP requires a prescription from a licensed healthcare provider, as it is an antibiotic and is not available over the counter. This prescription can be secured through various sources, including primary care physicians, specialized sexual health clinics, and certain telehealth services. Telehealth has become an increasingly accessible option, particularly for those already using services like HIV PrEP, since Doxy-PEP is often integrated into those prevention programs.
The consultation process involves a detailed risk assessment before a prescription is issued. Providers typically require baseline STI screening for syphilis, chlamydia, and gonorrhea, along with an HIV test, to ensure any existing infections are treated first. This screening is necessary because Doxy-PEP is a preventive measure, and the single dose is not strong enough to treat an established infection.
When speaking with a provider, it is helpful to ask specifically about Doxy-PEP, as it is a relatively new strategy and some practitioners may still be learning about it. The provider will then issue a prescription supply, which should last until the next scheduled follow-up visit, typically three to six months later. This ensures the medication is on hand for self-administration immediately following a potential exposure.
Doxy-PEP Administration Guidelines
The protocol for using Doxy-PEP relies on timely administration after a potential exposure. The prescribed medication is a 200 mg dose of doxycycline, which should be taken as soon as possible after having oral, vaginal, or anal sex without barrier protection. The ideal timing is within 24 hours of the event, but the medication remains effective when taken up to 72 hours post-exposure.
Doxy-PEP is a single post-exposure dose, not a daily regimen like PrEP. An individual should not take more than one 200 mg dose within a 24-hour period, regardless of sexual activity frequency. Taking the dose with a full glass of water and remaining upright for at least 30 minutes is recommended to prevent esophageal irritation. For optimal absorption, avoid taking the dose within two hours of consuming dairy products, antacids, or supplements containing calcium, iron, or magnesium.
Monitoring and Follow-Up Care
The use of Doxy-PEP is part of a comprehensive sexual health plan that requires ongoing monitoring and follow-up care. Routine STI testing remains necessary, even while using Doxy-PEP, with screening recommended every three to six months. These follow-up visits allow the provider to test for any breakthrough infections and reassess the ongoing need for the medication.
Doxycycline can cause side effects, with the most common being gastrointestinal upset, such as nausea or reflux, which can often be mitigated by taking the dose with food. The antibiotic also increases sensitivity to sunlight, meaning users should wear sunscreen and protective clothing to avoid severe sunburn. Providers will also monitor for the potential long-term public health concern of antimicrobial resistance, though current guidelines prioritize the individual benefit of preventing STIs.