Doxycycline Dosage for Lyme Disease

For early Lyme disease in adults, doxycycline 100 mg orally twice daily for 10-14 days is the preferred first-line treatment. 1, 2, 3

Adult Dosing by Clinical Presentation

Doxycycline 100 mg orally twice daily for 10-14 days is the recommended regimen 2, 3
The 10-day duration is sufficient for doxycycline due to its pharmacokinetic properties, while alternative agents require 14 days 3
Doxycycline has the critical advantage of treating co-infection with Human Granulocytic Anaplasmosis (HGA), which may occur simultaneously with Lyme disease 2, 3

Doxycycline 200-400 mg per day orally in 2 divided doses for 10-28 days is an acceptable alternative to intravenous therapy for neurologic involvement 2
For more severe neurological manifestations, intravenous ceftriaxone (2 g once daily) remains the preferred parenteral option 1

Doxycycline 4 mg/kg per day in 2 divided doses (maximum 100 mg per dose) for early Lyme disease 2

Doxycycline 4-8 mg/kg per day in 2 divided doses (maximum 100-200 mg per dose) for 10-28 days 2

Single dose of doxycycline 4 mg/kg (maximum 200 mg) when all criteria are met: tick identified as Ixodes scapularis, attached ≥36 hours, prophylaxis can start within 72 hours of removal, and local infection rate is ≥20% 2

Administer with 8 ounces of fluid to reduce esophageal irritation 2
Can be taken with food to reduce gastrointestinal intolerance 2
Advise patients to avoid sun exposure due to photosensitivity risk (15% of patients experience photosensitivity reactions) 2, 4

Pregnancy and lactation (relative contraindication) 2
Children <8 years of age (relative contraindication, though evolving) 2
For these populations, use amoxicillin 500 mg three times daily for 14 days or cefuroxime axetil 500 mg twice daily for 14 days 1, 2, 3

Never use first-generation cephalosporins (e.g., cephalexin) as they are completely ineffective against B. burgdorferi 1, 2, 3
Avoid macrolide antibiotics (azithromycin, clarithromycin, erythromycin) as first-line therapy—they are significantly less effective than doxycycline and should only be reserved for patients intolerant of all first-line agents 1, 2, 3
Do not extend treatment beyond recommended durations—there is no evidence that longer courses improve outcomes, and they increase risk of harm 1
Do not use combination antibiotic therapy, pulsed-dosing, or long-term antibiotics—these approaches lack efficacy and carry potential for harm 1

Most patients respond promptly and completely to appropriate antibiotic therapy 3
Treatment failure is uncommon (<10%) but may require reassessment for possible CNS involvement 3
Jarisch-Herxheimer-like reactions may occur within the first 24 hours of treatment but are typically mild and transient (29% with cefuroxime, 8% with doxycycline) 3, 4