Doxy PEP

Prescription Medication Information

This page provides information for Doxy PEP (doxycycline hyclate) 100 mg tablets. Doxy PEP is a prescription antibiotic used as post-exposure prophylaxis to prevent bacterial sexually transmitted infections (STIs) after sexual activity. The information provided is for educational purposes only and does not replace professional medical advice.

Critical Safety Notice

This is a prescription medication. It is not available over-the-counter. A licensed healthcare provider must evaluate your medical history, risk factors, and current health status to determine if Doxy PEP is appropriate for you. Do not use this medication without a valid prescription and proper medical supervision [citation:9].

What Is Doxy PEP?

Doxy PEP stands for Doxycycline Post-Exposure Prophylaxis. It is a novel, patient-managed biomedical STI prevention strategy recommended by the CDC for individuals at higher risk of bacterial STIs [citation:1][citation:3]. Unlike HIV PrEP (taken before exposure), Doxy PEP is taken after sex to prevent infections from taking hold [citation:2].

Who Is Doxy PEP For?

CDC guidelines recommend Doxy PEP for individuals who are at higher risk of bacterial STIs, including [citation:1][citation:9]:

• Gay, bisexual, and other men who have sex with men (MSM)
• Transgender women (TGW)
• Individuals with a history of at least one bacterial STI (syphilis, chlamydia, or gonorrhea) in the past 12 months

Additional populations who may benefit include [citation:1]:

• Those with multiple sexual partners
• Individuals engaging in condomless sex
• People in open or non-monogamous relationships
• Anyone at ongoing high risk for bacterial STIs as determined by their healthcare provider

Note: Current evidence does not support the use of Doxy PEP in cisgender women, as clinical trials did not demonstrate effectiveness in this population, likely due to adherence issues [citation:7].

How to Take Doxy PEP

Based on CDC guidelines and clinical trial data [citation:1][citation:2][citation:6]:

• Dosage: Take two 100 mg tablets (200 mg total) as a single dose
• Timing: Take as soon as possible, ideally within 24 hours and no later than 72 hours after oral, anal, or vaginal sex [citation:1][citation:6]
• Frequency: Do not take more than 200 mg within a 24-hour period. If you have sex again within 24 hours, wait 24 hours after your last dose before taking another [citation:2][citation:6]
• Administration: Take with a full glass of water and remain upright for at least 30 minutes afterward to prevent esophageal irritation [citation:6]
• With Food: May be taken with food if nausea occurs [citation:6]

STIs Prevented by Doxy PEP

Clinical trials have demonstrated that Doxy PEP significantly reduces the risk of [citation:1][citation:3][citation:10]:

• Chlamydia: Reduced by >70% (up to 70-89% effectiveness)
• Syphilis: Reduced by >70% (73-87% effectiveness)
• Gonorrhea: Reduced by approximately 50%

Doxy PEP does NOT prevent [citation:2][citation:10]:

• HIV (human immunodeficiency virus) – HIV PrEP is still needed
• Viral infections such as herpes, HPV (genital warts), or hepatitis

Important Safety Information

• Contraindications: Do not use if you are pregnant, allergic to doxycycline or other tetracycline antibiotics [citation:2][citation:10]
• Drug Interactions: Avoid taking with antacids, calcium supplements, iron, magnesium, aluminum, or bismuth subsalicylate (Pepto-Bismol) within 2 hours before or after dose, as they reduce effectiveness [citation:6][citation:10]
• Medication Interactions: Inform your doctor if you take acne treatments (isotretinoin), blood thinners (warfarin), epilepsy medications, or other antibiotics [citation:2][citation:10]
• Alcohol: Chronic heavy alcohol use may decrease effectiveness discuss with your provider [citation:6]
• Common Side Effects: Nausea, vomiting, headache, reflux, photosensitivity (sun sensitivity) [citation:2][citation:6]
• Photosensitivity: Wear high-SPF sunscreen and avoid tanning beds while taking doxycycline [citation:6][citation:10]
• Serious Side Effects: Severe headache, vision changes, or severe skin reactions require immediate medical attention

Regular STI Testing Required

Persons prescribed Doxy PEP should undergo bacterial STI testing at anatomic sites of exposure at baseline and every 3-6 months thereafter. Ongoing need for Doxy PEP should be assessed every 3-6 months as well [citation:1][citation:3]. HIV screening should also be performed according to current recommendations [citation:1].

Important Considerations

• Antibiotic Resistance: There are ongoing concerns about the potential for doxycycline to contribute to antimicrobial resistance in bacterial pathogens. Your healthcare provider will weigh the benefits and risks for your specific situation [citation:1][citation:4].
• Comprehensive Sexual Health: Doxy PEP should be implemented as part of a comprehensive sexual health approach, including risk reduction counseling, STI screening and treatment, recommended vaccinations (HPV, hepatitis), and linkage to HIV PrEP or HIV care as appropriate [citation:1][citation:9].
• Not a Replacement for Condoms: Condoms remain highly effective at preventing STIs and should be used consistently when possible.