Oral Amoxicillin Compared to Penicillin G Benzathine for the Treatment of Acquired Syphilis.

Participants randomized to the intervention group will receive oral amoxicillin at a dose of 40-50 mg/kg/day (maximum 1500 mg/day), administered in three doses daily for 14 days for early syphilis and 21 days for late syphilis or syphilis of unknown duration.

Participants randomized to the control group will receive intramuscular procaine benzathine penicillin (PGB) at a dose of 50,000 IU/kg (maximum 2,400,000 IU/day), administered as a single dose for early syphilis and as three consecutive weekly doses for late syphilis or syphilis of unknown duration.