How much doxycycline should be taken for ticks? - briefly
The typical prophylactic regimen after a potentially disease‑transmitting tick bite is 200 mg of doxycycline taken orally once daily for 21 days. For confirmed infections, the common therapeutic dose is 100 mg taken twice daily for 14–21 days.
How much doxycycline should be taken for ticks? - in detail
Doxycycline is the drug of choice for preventing and treating most tick‑borne infections. The recommended amount depends on the purpose (prophylaxis versus therapy), patient age, weight, and renal function.
For a single‑dose preventive regimen after an attached tick bite from a species known to transmit Borrelia burgdorferi (e.g., Ixodes scapularis in endemic areas), an adult should receive 200 mg orally within 72 hours of removal. Children weighing less than 45 kg are not eligible for this prophylaxis; instead, they should be monitored and treated if infection develops.
Therapeutic dosing for established infections follows these standards:
- Early localized Lyme disease: 100 mg twice daily for 10–14 days.
- Early disseminated or late Lyme disease: 100 mg twice daily for 21–28 days.
- Rocky Mountain spotted fever: 100 mg twice daily for adults; children receive 2.2 mg/kg every 12 hours, administered for at least 7 days and continued until 3 days after fever resolution.
- Anaplasmosis and Ehrlichiosis: 100 mg twice daily for adults; pediatric dose is 2.2 mg/kg every 12 hours, typically for 7–14 days.
Adjustments for renal impairment are required when creatinine clearance falls below 30 mL/min. The dose should be reduced to 100 mg once daily, or an alternative agent such as azithromycin considered if severe dysfunction is present.
Pregnant or lactating women should avoid doxycycline because of potential fetal bone growth inhibition and tooth discoloration in infants. In such cases, alternatives (e.g., amoxicillin for Lyme disease) are preferred.
Compliance with the full course is essential; premature discontinuation may lead to relapse or resistance. Monitoring for adverse effects—photosensitivity, gastrointestinal upset, and, rarely, esophageal ulceration—should be part of patient counseling.