Which antibiotic is first-line for Lyme arthritis in adults?

Which antibiotic is first-line for Lyme arthritis in adults?

• A. Doxycycline
• B. Azithromycin
• C. Ciprofloxacin
• D. Metronidazole

Answer: (A)

Lyme arthritis in adults is treated most effectively with an oral antibiotic that reliably targets Borrelia burgdorferi and can be taken at home. Doxycycline fits this role well because it has strong activity against the organism and penetrates joint tissue well, allowing a convenient 28-day course without the need for hospitalization. Its tolerability and once-daily dosing, when necessary, make it a practical first choice for outpatient therapy. Other options listed either don’t work as well against Borrelia or aren’t recommended for this presentation. Azithromycin is less effective and associated with higher relapse rates; ciprofloxacin isn’t reliably active against Borrelia; metronidazole has no meaningful activity against this organism. If doxycycline isn’t suitable, alternatives include amoxicillin or cefuroxime for 28 days, with IV ceftriaxone reserved for more severe disease or treatment failure.

Lyme arthritis in adults is treated most effectively with an oral antibiotic that reliably targets Borrelia burgdorferi and can be taken at home. Doxycycline fits this role well because it has strong activity against the organism and penetrates joint tissue well, allowing a convenient 28-day course without the need for hospitalization. Its tolerability and once-daily dosing, when necessary, make it a practical first choice for outpatient therapy.

Other options listed either don’t work as well against Borrelia or aren’t recommended for this presentation. Azithromycin is less effective and associated with higher relapse rates; ciprofloxacin isn’t reliably active against Borrelia; metronidazole has no meaningful activity against this organism. If doxycycline isn’t suitable, alternatives include amoxicillin or cefuroxime for 28 days, with IV ceftriaxone reserved for more severe disease or treatment failure.