From the Guidelines
For a one-time dose of doxycycline, the 200mg delayed release formulation is the preferred choice. This recommendation is based on the most recent guidelines from the CDC, which suggest that a 200mg dose of doxycycline taken within 72 hours after sex can reduce syphilis and chlamydia infections by >70% and gonococcal infections by approximately 50% 1. The 200mg delayed release formulation is specifically designed for single-dose therapy and provides appropriate drug levels with better gastrointestinal tolerance.
Some key points to consider when using doxycycline for postexposure prophylaxis include:
- The recommended dose of doxy PEP is 200mg and should not exceed a maximum dose of 200mg every 24 hours 1
- Doxy PEP should be implemented in the context of a comprehensive sexual health approach, including risk reduction counseling, STI screening and treatment, recommended vaccination and linkage to HIV PrEP, HIV care, or other services as appropriate 1
- Persons who are prescribed doxy PEP should undergo bacterial STI testing at anatomic sites of exposure at baseline and every 3–6 months thereafter 1
It's essential to follow the recommended dosing schedule and take the medication as directed to minimize side effects and ensure effectiveness. Additionally, patients should be aware of potential interactions with other medications, such as dairy products, antacids, or iron supplements, which can reduce absorption 1.
From the FDA Drug Label
Adults: The usual dose of oral doxycycline is 200 mg on the first day of treatment (administered 100 mg every 12 hours) Uncomplicated gonococcal infections in adults (except anorectal infections in men):100 mg, by mouth, twice a day for 7 days. As an alternate single visit dose, administer 300 mg stat followed in one hour by a second 300 mg dose.
The recommended single dose for doxycycline is not 100mg tabs or 200mg delayed release. However, the usual dose of oral doxycycline is 200 mg on the first day of treatment, which can be administered as 100 mg every 12 hours. For uncomplicated gonococcal infections, an alternate single visit dose is 300 mg stat followed in one hour by a second 300 mg dose 2.
From the Research
Dosage Forms of Doxycycline
- 100mg tabs: No specific information is available in the provided studies regarding the use of 100mg tabs for a one-time dose of doxycycline 3, 4, 5, 6, 7.
- 200mg delayed release: A study published in 2008 mentions the use of single-dose doxycycline (200 mg orally) as prophylaxis in selected patients for Lyme disease 7.
Efficacy and Safety
- The efficacy and safety of doxycycline have been evaluated in various studies, including those for the treatment of papulopustular rosacea and bacterial sexually transmitted infections 4, 5, 6.
- A study published in 2012 found that modified-release doxycycline capsules (30 mg immediate-release and 10 mg delayed-release beads) were effective and safe as monotherapy for papulopustular rosacea in both male and female patients 5.
- Another study published in 2010 found that doxycycline 40 mg (30-mg immediate-release and 10-mg delayed-release beads) was effective and well-tolerated as add-on therapy to existing topical regimens for the treatment of papulopustular rosacea 6.