6/28/23, 11:02 PM Low-dose amoxicillin in syphilis Pathway Feedback Search Clinical Topics Home Studies Low-dose amoxicillin in syphilis Low-dose amoxicillin in syphilis Disease Syphilis infection Trial question Is low-dose amoxicillin monotherapy noninferior to the combination of amoxicillin and probenecid for treating syphilis in patients with human immunodeficiency virus infection? Study design Single center Open label RCT Population 112 patients Inclusion criteria: patients with human immunodeficiency virus infection and syphilis Key exclusion criteria: pregnancy; amoxicillin or probenecid allergy; diagnosis of otosyphilis, ocular syphilis or neurosyphilis; antibiotic use 3 weeks before diagnosis Interventions N=56 amoxicillin monotherapy (at a dose of 500 mg PO TID) N=56 amoxicillin plus probenecid (amoxicillin 1,000 mg PO TID plus probenecid 250 mg PO TID) Primary outcome Rate of serological cure rate for overall syphilis within 12 months 94.4 % 94.4 90.6 70.8 % 47.2 % Difference exceeding nonferiority margin 23.6 % 0.0 % https://web.pathway.md/studies/recaOxPxsTckSy6qw 1/2 6/28/23, 11:02 PM Low-dose amoxicillin in syphilis Pathway Amoxicillin monotherapy Amoxicillin plus probenecid Difference exceeding nonferiority margin in the rate of serological cure rate for overall syphilis within 12 months (90.6% vs. 94.4%; ARD -3.8, 95% CI -13.48 to 5.88) Conclusion In patients with human immunodeficiency virus infection and syphilis, amoxicillin monotherapy was not noninferior to amoxicillin plus probenecid with respect to the rate of serological cure rate for overall syphilis within 12 months. Reference Naokatsu Ando, Daisuke Mizushima, Kazumi Omata et al. Combination of Amoxicillin 3,000 mg and Probenecid versus 1,500 mg Amoxicillin Monotherapy for Treating Syphilis in Patients with HIV: an Open-Label, Randomized, Controlled, Non-Inferiority Trial. Clin Infect Dis. 2023 May 9;ciad278. Open reference URL https://web.pathway.md/studies/recaOxPxsTckSy6qw 2/2