Doxycycline Prophylaxis Dosage Recommendations
The recommended dosage for doxycycline prophylaxis is 200 mg taken as a single dose within 72 hours after potential exposure, not to exceed 200 mg per 24 hours. 1
Doxycycline Postexposure Prophylaxis (Doxy PEP) for STIs
Recommended Population and Dosage
- CDC recommends doxycycline PEP for gay, bisexual, and other men who have sex with men (MSM) and transgender women (TGW) with a history of at least one bacterial STI in the past 12 months 1
- The recommended dose is 200 mg (any formulation) taken once within 72 hours after oral, vaginal, or anal sex 1
- Maximum dosage should not exceed 200 mg per 24 hours 1
- The medication should be taken as soon as possible after sexual exposure, but no later than 72 hours 1
Administration Guidelines
- Take doxycycline on a full stomach with a full glass of liquid 1
- Avoid lying down for at least 1 hour after taking doxycycline to prevent esophagitis 1, 2
- Separate doxycycline dose by at least 2 hours from dairy products, antacids, and supplements containing calcium, iron, magnesium, or sodium bicarbonate 1, 2
- Prescription should account for enough doses based on anticipated sexual activity until the next follow-up visit 1
Monitoring and Follow-up
- Ongoing need for doxy PEP should be assessed every 3-6 months 1
- STI screening should be performed at baseline and every 3-6 months at anatomic sites of exposure 1
- Assess for side effects from doxycycline at follow-up visits 1
Doxycycline Prophylaxis for Lyme Disease
- For prevention of Lyme disease after an Ixodes scapularis tick bite, a single 200 mg dose of doxycycline is recommended within 72 hours of tick removal 1, 3
- This prophylaxis has shown 87% efficacy in preventing Lyme disease 3
- Prophylaxis is indicated when all of the following criteria are met:
- The attached tick can be reliably identified as an adult or nymphal Ixodes scapularis tick estimated to have been attached for ≥36 hours
- Prophylaxis can be started within 72 hours after tick removal
- Local rate of infection of ticks with Borrelia burgdorferi is ≥20%
- Doxycycline is not contraindicated 1
Doxycycline Prophylaxis for Malaria
- For adults: 100 mg daily 4
- For children over 8 years of age: 2 mg/kg given once daily up to the adult dose 4
- Prophylaxis should begin 1-2 days before travel to the malarious area, continue daily during travel, and for 4 weeks after leaving the malarious area 4
Common Side Effects and Precautions
- Common side effects include photosensitivity, esophagitis, gastrointestinal intolerance (nausea, vomiting, diarrhea) 1, 2
- Chronic alcohol consumption may reduce serum levels of doxycycline, potentially decreasing its efficacy 2
- Avoid direct exposure to sunlight or UV radiation during treatment due to risk of photosensitivity 2
Special Considerations
- For STI prophylaxis in populations other than MSM and TGW (such as cisgender women, cisgender heterosexual men, transgender men, and other queer and nonbinary persons), evidence is currently insufficient to make formal recommendations 1
- Recent research suggests limited efficacy of doxycycline PEP for preventing STIs in cisgender women, with no significant difference compared to standard care 5