How many antibiotics should be taken after a tick bite? - briefly
«A single prophylactic dose of doxycycline (200 mg) given within 72 hours of a high‑risk tick bite is recommended; if infection develops, a therapeutic course of 10–14 days is prescribed.» «When doxycycline cannot be used, amoxicillin for 5–7 days serves as an alternative.»
How many antibiotics should be taken after a tick bite? - in detail
The decision on antibiotic therapy after a tick bite depends on the species of tick, attachment time, and local disease prevalence. Prophylactic treatment is recommended only when the risk of infection exceeds a defined threshold.
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If a nymphal or adult Ixodes scapularis has been attached for ≥ 36 hours in an area where the incidence of Lyme disease is ≥ 20 cases per 100 000 population, a single dose of doxycycline 200 mg taken orally within 72 hours of removal is advised. This regimen has been shown to reduce the likelihood of early Lyme disease by approximately 87 %.
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For children younger than 8 years, doxycycline is contraindicated; amoxicillin 50 mg/kg as a single dose (maximum 2 g) may be used under the same risk criteria.
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When the tick is identified as a species not associated with Lyme disease (e.g., Dermacentor spp. in regions without Rocky Mountain spotted fever), prophylaxis is not indicated unless other pathogen transmission is suspected.
If prophylaxis is not administered and symptoms of infection appear (erythema migrans, fever, arthralgia, neurologic signs), a therapeutic course is required:
- Doxycycline 100 mg twice daily for 10–14 days is the first‑line treatment for uncomplicated Lyme disease in adults and children ≥ 8 years.
- For patients with contraindications to doxycycline, amoxicillin 500 mg three times daily for 14 days or cefuroxime axetil 500 mg twice daily for 14 days are acceptable alternatives.
- In cases of neurologic involvement or severe manifestations, intravenous ceftriaxone 2 g once daily for 14–21 days is recommended.
Pregnant and lactating individuals should avoid doxycycline; oral amoxicillin 500 mg three times daily for 14 days is the preferred regimen.
Monitoring after the bite includes inspection of the bite site for expanding erythema and assessment for systemic signs. Immediate medical evaluation is warranted for fever, severe headache, facial palsy, or joint swelling.