What is the recommended doxycycline dosage for an adult after a tick bite? - briefly
The recommended adult regimen is 100 mg doxycycline taken orally twice daily for 14 days. This dosage is advised for prophylaxis following a tick bite.
What is the recommended doxycycline dosage for an adult after a tick bite? - in detail
The prophylactic regimen for an adult who has been bitten by a tick and is at risk for Lyme disease consists of doxycycline 100 mg taken twice daily. The course lasts 21 days and should be initiated within 72 hours of the bite. This schedule provides sufficient serum concentrations to prevent early infection.
Key points for implementation:
- Dosage: 100 mg oral tablet every 12 hours.
- Duration: 21 days, continuous administration.
- Initiation window: Start treatment no later than three days after exposure.
- Renal adjustment: For creatinine clearance below 30 mL/min, reduce dose to 50 mg twice daily or consider alternative agents.
- Contraindications: Pregnancy, lactation, known hypersensitivity to tetracyclines, and children under eight years of age.
- Common adverse effects: Gastrointestinal upset, photosensitivity, and transient esophageal irritation; advise taking the tablet with a full glass of water and remaining upright for at least 30 minutes.
- Drug interactions: Avoid concurrent use of isotretinoin, oral anticoagulants, and antacids containing aluminum, calcium, magnesium, or iron, as these may reduce absorption.
If the tick bite occurred in an area where other tick‑borne pathogens predominate, or if the bite was attached for more than 24 hours, clinicians may consider additional evaluation and alternative prophylaxis. Monitoring for rash, fever, or arthralgia during the treatment period is recommended to detect breakthrough infection early.