Amoxycillin plus probenecid versus doxycycline for treatment of erythema migrans borreliosis.

72 adults with erythema migrans (early Lyme borreliosis) were enrolled in a randomised prospective trial comparing amoxycillin 500 mg plus probenecid 500 mg three times a day with doxycycline 100 mg twice a day for 21 days. These antibiotic regimens were chosen because of the known in-vitro sensitivity of Borrelia burgdorferi, the antibiotic tissue penetration, the pharmacokinetics of the drugs, and because the organism can disseminate early in the course of infection. 72 patients were evaluable (35 in the doxycycline group and 37 in the amoxycillin/probenecid group). The two regimens were equally effective for treatment of erythema migrans. Mild fatigue or arthralgia were the only post-treatment complaints, which resolved within 6 months. None of the patients needed further antibiotic treatment for Lyme borreliosis.