In nonpregnant adults with early localized Lyme disease, which is first-line therapy?

• A. Doxycycline 100 mg twice daily for 10–21 days
• B. Amoxicillin 500 mg three times daily for 14 days
• C. Cefuroxime axetil 500 mg twice daily for 14 days
• D. Azithromycin 500 mg daily for 5 days

Answer: (A)

Doxycycline is the first-line choice for treating early localized Lyme disease in nonpregnant adults because it effectively covers Borrelia burgdorferi, reaches good tissue levels, and is conveniently taken orally for a short course (typically 10–21 days). This option balances strong efficacy with tolerability and ease of use, making it the preferred initial therapy.

Amoxicillin and cefuroxime axetil are acceptable alternatives when doxycycline isn’t suitable (for example, in pregnancy, lactation, or children under 8). Azithromycin is not recommended as first-line due to lower efficacy and higher relapse rates.