Possible Unlikely Serologic criterion one or two with ≤1 minor criterion Maternal history of adequate treatment during pregnancy (penicillin-based regimen) + nonreactive serologic test for syphilis XR, radiographs; CNS, central nervous system; CSF, cerebrospinal fluid; RPR, rapid plasma reagin; VDRL, venereal disease research laboratory; FTA-ABS, fluorescent treponemal antibody absorption; TP-PA, Treponema pallidum particle agglutination; MHA-TP, microhemagglutination test for antibodies to Treponema pallidum Modified from Mascola L, Pelosi R, Blount JH, et al Congenital syphilis revisited Am J Dis Child 1985;139:575–580 e-TABLE 94.32 TREATMENT OF SYPHILIS Stage Primary, secondary, or early latent (infection within the last 12 mo) Treatment Penicillin G benzathine 50,000 units/kg (maximum: 2.4 million units) IM once Late latent (>1 yr since acquisition), Penicillin G benzathine 50,000 latent syphilis of unknown duration, units/kg (maximum: 2.4 million or tertiary syphilis units) IM weekly for wks Congenital syphilis or neurosyphilis Aqueous penicillin G 50,000 units/kg/dose IV every 12 hrs in 0–7 do, then every hrs in infants > days (maximum daily dose: 24 million units/day) for 10 days Alternative regimen for adults: Procaine penicillin G 24 million units IM daily with probenecid 500 mg four times daily for 10–14 days IM, intramuscular; IV, intravenous