What is the dosage and administration of doxycycline (Doxycycline) for pre-exposure prophylaxis (PrEP)?

Doxycycline Post-Exposure Prophylaxis (Doxy PEP) for STI Prevention

The recommended dosage for doxycycline post-exposure prophylaxis (doxy PEP) for STI prevention is 200 mg taken as a single dose as soon as possible within 72 hours after sexual exposure, not to exceed 200 mg per 24 hours. 1

Patient Population and Eligibility

• Doxy PEP is specifically recommended for:

  • Gay, bisexual, and other men who have sex with men (MSM)
  • Transgender women (TGW)
  • Who have had at least one bacterial STI (syphilis, chlamydia, or gonorrhea) diagnosed in the past 12 months 1

• Currently, there is insufficient evidence to recommend doxy PEP for:

  • Cisgender women
  • Cisgender heterosexual men
  • Transgender men
  • Other queer and nonbinary persons 1

Prescription Details

1. Dosage: 200 mg doxycycline (any formulation) 1
2. Timing: Take as soon as possible after sexual exposure, but within 72 hours 1
3. Frequency: Maximum of 200 mg per 24-hour period 1
4. Duration: Prescribe enough doses based on anticipated sexual activity until next follow-up visit 1
5. Administration: Take with food or milk and a full glass of water to reduce gastrointestinal side effects 1, 2
6. Position after taking: Remain upright for at least 1 hour after taking to prevent esophageal irritation 1

Effectiveness

• Doxy PEP has demonstrated significant reductions in bacterial STI acquisition:

  • 70% reduction in syphilis and chlamydia infections

  • Approximately 50% reduction in gonococcal infections 1

Monitoring and Follow-up

• Baseline STI testing at initiation (nucleic acid amplification test for gonorrhea and chlamydia at anatomic sites of exposure and serologic testing for syphilis) 1
• Follow-up STI testing every 3-6 months 1
• Reassess ongoing need for doxy PEP every 3-6 months 1
• For persons without HIV infection not on PrEP, consider HIV screening every 3-6 months 1

Patient Counseling Points

• Explain proper timing and dosing (as soon as possible after sex, within 72 hours)
• Discuss potential side effects:
  • Photosensitivity
  • Esophagitis and esophageal discomfort
  • Gastrointestinal intolerance (nausea, vomiting, diarrhea) 1
• Take with food and plenty of fluid to minimize GI side effects
• Remain upright for at least 1 hour after taking
• Do not exceed 200 mg in a 24-hour period
• Use only for its intended purpose

Important Caveats and Considerations

• Doxy PEP is distinct from pre-exposure prophylaxis (PrEP), which involves taking medication before exposure 1

• Doxy PEP should be implemented as part of a comprehensive sexual health approach, including:

  • Risk reduction counseling
  • Regular STI screening and treatment
  • Recommended vaccinations
  • HIV PrEP or treatment as appropriate 1

• While doxycycline is used for prophylaxis in other conditions like Lyme disease 3, 4, the specific dosing for STI prevention differs from these other indications

Clinical Pitfalls to Avoid

• Do not exceed 200 mg per 24-hour period, as higher doses may increase side effects 2
• Do not prescribe without appropriate counseling about timing (within 72 hours of exposure)
• Do not neglect regular STI testing every 3-6 months
• Do not use doxy PEP as a replacement for other STI prevention strategies
• Do not prescribe without discussing proper administration (with food/water, staying upright)