Doxycycline PEP Formulation for STI Prevention
The CDC guidelines explicitly state that doxycycline PEP can be prescribed as "any formulation" of 200 mg to be taken within 72 hours after sexual contact, indicating that delayed-release formulations are acceptable for doxy PEP. 1
Formulation Options for Doxy PEP
- The 2024 CDC clinical guidelines specifically mention that "doxycycline (any formulation) 200 mg" can be used for PEP purposes
- This means that both immediate-release and delayed-release formulations are appropriate options for doxy PEP
- The focus is on the 200 mg dose rather than a specific formulation type
Administration Recommendations
- Doxycycline PEP should be taken as a single 200 mg dose within 72 hours after condomless sexual contact
- Maximum dosing should not exceed 200 mg per 24-hour period 1
- Should be taken with a full stomach and a full glass of liquid
- Patient should remain upright for at least 1 hour after taking to prevent esophagitis 2
- Separate doses from dairy products, antacids, and supplements containing calcium, iron, magnesium, or sodium bicarbonate by at least 2 hours 2
Target Population and Efficacy
- Primarily recommended for MSM and transgender women with history of bacterial STI in the past 12 months 1
- Clinical trials have demonstrated significant reductions in:
Clinical Considerations
- Prescription should account for enough doses based on the person's anticipated sexual activity until their next visit 1
- Ongoing need for doxy PEP should be assessed every 3-6 months 1
- Regular STI screening at anatomic sites of exposure is recommended quarterly 2
Potential Side Effects and Precautions
- Common side effects include photosensitivity, esophagitis, gastrointestinal intolerance 1
- Not recommended during pregnancy due to potential risks including dental staining of fetal primary teeth 2
- May reduce effectiveness of oral contraceptives 2
- Development of antimicrobial resistance is a significant concern, particularly for gonorrhea 2, 4
Key Takeaway
The formulation type (immediate-release vs. delayed-release) is not specified in the guidelines, making either formulation appropriate for doxy PEP as long as the correct 200 mg dose is administered within the recommended timeframe.