From the Guidelines
The recommended doxycycline regimen for treating infections is typically 100 mg taken orally twice daily (every 12 hours) for 7-14 days, depending on the specific infection being treated. For most common bacterial infections, a 7-day course is sufficient, while more severe or complicated infections may require the full 14-day treatment 1. Doxycycline should be taken with a full glass of water, and patients should remain upright for at least 30 minutes after taking it to prevent esophageal irritation. The medication can be taken with food if stomach upset occurs, although dairy products, antacids, iron supplements, and calcium supplements should be avoided within 2 hours of taking doxycycline as they can reduce absorption. Doxycycline works by inhibiting bacterial protein synthesis, preventing bacteria from growing and multiplying. It's effective against a wide range of bacteria including those causing respiratory, urinary tract, and skin infections, as well as certain sexually transmitted infections. Patients should complete the full prescribed course even if symptoms improve before the medication is finished to ensure complete eradication of the infection and reduce the risk of antibiotic resistance.
Some key points to consider when prescribing doxycycline include:
- The dosage and duration of treatment may vary depending on the specific infection being treated, with some infections requiring a longer course of treatment 1.
- Doxycycline is contraindicated in children under 8 years of age and in pregnant or breastfeeding women, except in cases where the benefits outweigh the risks 1.
- Patients should be advised to avoid exposure to sunlight while taking doxycycline, as it can cause photosensitivity 1.
- Doxycycline can interact with other medications, such as antacids and iron supplements, which can reduce its absorption 1.
Overall, doxycycline is a effective and widely used antibiotic for treating a range of bacterial infections, and its recommended regimen is typically 100 mg taken orally twice daily for 7-14 days. However, the specific dosage and duration of treatment may vary depending on the individual patient and the specific infection being treated.
From the FDA Drug Label
The usual dosage of doxycycline hyclate tablet is 200 mg on the first day of treatment (administered 100 mg every 12 hours) followed by a maintenance dose of 100 mg daily.
For certain selected specific indications, the recommended duration or dosage and duration of doxycycline hyclate tablets and capsules in adult patients are as follows:
- Streptococcal infections, therapy should be continued for 10 days
- Uncomplicated urethral, endocervical, or rectal infection caused by Chlamydia trachomatis: 100 mg by mouth twice-a-day for 7 days.
- Uncomplicated gonococcal infections in adults (except anorectal infections in men): 100 mg, by mouth, twice-a-day for 7 days.
- Nongonococcal urethritis (NGU) caused by C. trachomatis and U. urealyticum: 100 mg by mouth twice‑a‑day for 7 days.
- Syphilis – early: Patients who are allergic to penicillin should be treated with doxycycline 100 mg by mouth twice-a-day for 2 weeks
- Syphilis of more than one year’s duration: Patients who are allergic to penicillin should be treated with doxycycline 100 mg by mouth twice-a-day for 4 weeks.
- Acute epididymo-orchitis caused by N. gonorrhoeae: 100 mg by mouth, twice-a-day for at least 10 days.
- Acute epididymo-orchitis caused by C. trachomatis: 100 mg, by mouth, twice-a-day for at least 10 days.
The recommended doxycycline regimen for treating infections is:
- Adults: 200 mg on the first day (100 mg every 12 hours), followed by 100 mg daily for the duration of the treatment, which varies depending on the type of infection.
- Pediatric patients:
- Weighing less than 45 kg with severe or life-threatening infections: 2.2 mg/kg every 12 hours.
- Weighing 45 kg or more: the usual adult dose.
- With less severe disease (over 8 years old and weighing less than 45 kg): 4.4 mg/kg on the first day, divided into two doses, followed by 2.2 mg/kg daily.
From the Research
Doxycycline Antibiotic Regimen for Infection
- The recommended doxycycline regimen for treating infections varies depending on the type of infection and the patient population 3, 4, 5, 6, 7.
- For the treatment of sexually transmitted infections (STIs), doxycycline is often used as a second-line treatment due to its efficacy, good tolerability, and oral administration 3.
- A study published in 2020 found that a doxycycline-moxifloxacin regimen was effective in treating Mycoplasma genitalium infection, with a microbial cure rate of 92.0% 4.
- Another study published in 2025 suggested that a one-time dose of 200 mg doxycycline taken within 72 hours of an unprotected sexual encounter may reduce transmission of syphilis, gonorrhea, and chlamydia by a combined two thirds in a high-risk population 5.
- A randomized controlled trial published in 2002 compared the effectiveness of azithromycin versus doxycycline/ciprofloxacin in the treatment of STIs in a resource-poor setting, and found that azithromycin was more effective in treating chlamydial infection 6.
- A retrospective cohort study published in 2014 compared the effectiveness of azithromycin and doxycycline in treating rectal chlamydial infection, and found that doxycycline may be more effective than azithromycin in this context 7.
Dosage and Administration
- The dosage and administration of doxycycline vary depending on the specific infection being treated and the patient population 3, 4, 5, 6, 7.
- For the treatment of STIs, doxycycline is often administered orally, with a typical dosage of 100 mg twice daily for 7 days 3, 4.
- A one-time dose of 200 mg doxycycline has also been suggested as a potential prophylactic treatment for STIs 5.