Doxycycline Dosing for Urinary Tract Infections
For uncomplicated UTIs caused by susceptible organisms, doxycycline 100 mg orally twice daily for 7 days is the recommended dose. 1
Standard Dosing Regimen
The FDA-approved dosing for doxycycline in urinary tract infections is:
- Initial dose: 200 mg on the first day (administered as 100 mg every 12 hours) 1
- Maintenance dose: 100 mg daily thereafter 1
- For severe or chronic UTIs: 100 mg every 12 hours is recommended 1
Specific UTI Contexts
Chlamydial Urethritis/Cervicitis
For uncomplicated urethral, endocervical, or rectal infections caused by Chlamydia trachomatis:
- Doxycycline 100 mg orally twice daily for 7 days 2, 1
- This is a CDC-recommended regimen with strong guideline support 2
Nongonococcal Urethritis (NGU)
For NGU caused by C. trachomatis or U. urealyticum:
- Doxycycline 100 mg orally twice daily for 7 days 1
- Alternative once-daily formulation: Doxycycline hyclate delayed-release 200 mg orally once daily for 7 days 2
Multidrug-Resistant UTIs
For susceptible multidrug-resistant organisms (including ESBL-producing bacteria):
- Doxycycline 100 mg orally twice daily based on susceptibility testing 3
- Doxycycline achieves high urinary concentrations and may be effective when susceptibility is confirmed 3
Important Clinical Considerations
Administration guidelines to minimize adverse effects:
- Take with a full glass of liquid and a full stomach 2
- Avoid lying down for 1 hour after dosing to prevent esophagitis 2, 1
- Separate dosing by at least 2 hours from dairy products, antacids, and supplements containing calcium, iron, magnesium, or sodium bicarbonate 2
Common pitfall: The usual maintenance dose is 100 mg daily for most infections, but UTIs—particularly chronic or severe cases—often require 100 mg every 12 hours for optimal efficacy 1. Do not underdose.
Duration considerations: While single-dose doxycycline (300 mg) has been studied for bacterial cystitis, it showed inferior efficacy compared to standard regimens and is not recommended 4. Short courses (4 days) showed comparable efficacy to 10-day courses in one small study 5, but the standard 7-day regimen remains preferred for reliability 2, 1.
Photosensitivity warning: Counsel patients about sun exposure risk and protective measures 2.