From the Guidelines
Doxycycline is typically dosed at 100 mg twice daily for the treatment of adult patients with early localized or early disseminated Lyme disease associated with erythema migrans. For acute infections, treatment usually lasts 10-14 days, while chronic conditions may require longer therapy 1. Specific conditions have tailored regimens: for malaria prophylaxis, take 100 mg daily starting 1-2 days before travel and continuing for 4 weeks after return; for acne, 50-100 mg daily is common; for chlamydia, a single dose of 200 mg followed by 100 mg twice daily for 7 days is effective. Doxycycline should be taken with a full glass of water, either with food to reduce stomach upset or at least 1 hour before bedtime to prevent esophageal irritation. The medication works by inhibiting bacterial protein synthesis, preventing bacterial growth and reproduction. Patients should avoid dairy products, antacids, and supplements containing calcium, magnesium, aluminum, or iron within 2 hours of taking doxycycline as these can reduce absorption. Sun protection is essential during treatment due to increased photosensitivity, and the medication should be avoided in pregnant women and children under 8 years due to potential effects on bone development and tooth discoloration 1.
Some key points to consider when prescribing doxycycline include:
- The dosage for children 8 years of age is 4 mg/kg per day in 2 divided doses (maximum, 100 mg per dose) 1
- Doxycycline is relatively contraindicated in pregnant or lactating women and in children < 8 years of age 1
- Patients treated with doxycycline should be closely observed to ensure resolution of the clinical manifestations 1
- Doxycycline may cause photosensitivity, which is a concern, because early Lyme disease occurs most commonly during the summer months 1
It is essential to note that doxycycline should be used with caution in patients with impaired renal function, and the dosage should be reduced accordingly 1. Additionally, doxycycline should not be used in combination with other antimicrobials, as this may increase the risk of adverse effects 1.
In terms of treatment duration, 10 days of therapy is sufficient if doxycycline is used; however, given the much shorter half-life of β-lactam drugs, such as amoxicillin or cefuroxime axetil, it is unclear whether a 10-day course of these drugs would be as effective 1. Therefore, for uniformity, a 14-day course of therapy is recommended for all of the first-line oral agents.
Overall, doxycycline is a effective and well-tolerated antibiotic for the treatment of various infections, including Lyme disease. However, it is essential to use it judiciously and follow the recommended dosage and treatment duration to minimize the risk of adverse effects and ensure optimal outcomes.
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) followed by a maintenance dose of 100 mg/day For children above eight years of age: The recommended dosage schedule for children weighing 100 pounds or less is 2 mg/lb of body weight divided into two doses on the first day of treatment, followed by 1 mg/lb of body weight given as a single daily dose or divided into two doses, on subsequent days. Uncomplicated gonococcal infections in adults (except anorectal infections in men):100 mg, by mouth, twice a day for 7 days. Uncomplicated urethral, endocervical, or rectal infection in adults caused by Chlamydia trachomatis: 100 mg, by mouth, twice a day for 7 days. For the prophylaxis of malaria: For adults, the recommended dose is 100 mg daily. Inhalational anthrax (post-exposure): ADULTS: 100 mg of doxycycline, by mouth, twice a day for 60 days.
The appropriate dosing for doxycycline (tetracycline antibiotic) is:
- Adults: 200 mg on the first day, then 100 mg/day
- Children over 8 years and weighing 100 pounds or less: 2 mg/lb on the first day, then 1 mg/lb/day
- Children over 100 pounds: same as adult dose
- Specific infections:
- Uncomplicated gonococcal infections: 100 mg twice a day for 7 days
- Uncomplicated Chlamydia trachomatis infections: 100 mg twice a day for 7 days
- Malaria prophylaxis: 100 mg daily
- Inhalational anthrax (post-exposure): 100 mg twice a day for 60 days 2
From the Research
Dosing for Doxycycline
- The recommended dosing for doxycycline varies depending on the condition being treated and the patient population.
- For adults with early localized Lyme disease, doxycycline can be administered at a dose of 100 mg twice daily for 14 days 3.
- For children above 8 years of age, doxycycline can be administered at a dose of 4 mg/kg/day in 2 intakes, with a maximum dose of 100 mg/dose 3.
- In the treatment of multiple erythema migrans, oral doxycycline (100 mg q12h) has been compared to intravenous ceftriaxone (2 g q24h) for 14 days, with doxycycline showing non-inferiority 4.
- For patients with chronic Lyme borreliosis, doxycycline can be administered at a dose of 100 mg twice daily for 4 weeks, which has been found to be as effective as intravenous ceftriaxone 5.
- In general, doxycycline can be used as an alternative to amoxicillin, with a typical dose of 100 mg twice daily 6.