How many milligrams of doxycycline should be taken after a tick bite? - briefly
The standard prophylactic regimen is 200 mg of doxycycline taken once daily for 10–14 days, initiated as soon as possible and no later than 72 hours after the bite. This dosage is supported by CDC guidelines for preventing tick‑borne infections.
How many milligrams of doxycycline should be taken after a tick bite? - in detail
The standard prophylactic regimen for a tick exposure is a single oral dose of 200 mg doxycycline taken within 72 hours of the bite. This dosage is recommended for adults and children weighing at least 45 kg (approximately 99 lb). For patients under that weight threshold, the dose is adjusted to 4 mg per kilogram of body weight, not exceeding 200 mg.
Key points to consider:
- Timing – The medication must be started as soon as possible, ideally within three days after the bite. Delayed initiation reduces effectiveness in preventing Lyme disease.
- Age restrictions – Doxycycline is approved for prophylaxis in children older than eight years. For younger children, alternative antibiotics such as amoxicillin are preferred.
- Pregnancy and lactation – Use is contraindicated; other agents should be selected.
- Renal or hepatic impairment – Dose adjustment may be necessary; consult a healthcare professional.
- Allergy to tetracyclines – Substitute with an appropriate alternative, typically amoxicillin or cefuroxime.
If the bite is associated with a known infected tick or the patient presents with signs of early infection (e.g., erythema migrans), a therapeutic course of doxycycline is indicated: 100 mg twice daily for 10–21 days, depending on clinical judgment.
Adherence to the single‑dose protocol, proper timing, and consideration of patient‑specific factors are essential for effective prophylaxis.