Treatment for Latent Stage Syphilis

Introduction to Latent Syphilis Treatment

The Centers for Disease Control and Prevention recommends treating early latent syphilis with benzathine penicillin G 2.4 million units IM as a single dose, and late latent syphilis or latent syphilis of unknown duration with benzathine penicillin G 7.2 million units total administered as three doses of 2.4 million units IM at weekly intervals 1, 2

For early latent syphilis, the American College of Physicians and the Centers for Disease Control and Prevention recommend benzathine penicillin G 2.4 million units IM in a single dose as the first-line treatment 1, 2, 3
The Centers for Disease Control and Prevention defines early latent syphilis as diagnosed when patients have documented seroconversion, unequivocal symptoms of primary or secondary syphilis within the past year, or a sex partner with documented early syphilis 1, 2
For late latent syphilis or latent syphilis of unknown duration, the Centers for Disease Control and Prevention recommends benzathine penicillin G 7.2 million units total, administered as three doses of 2.4 million units IM at 1-week intervals 1, 2, 3

The Centers for Disease Control and Prevention recommends performing lumbar puncture before treatment if the patient has any of the following criteria: neurologic or ophthalmic signs or symptoms, evidence of active tertiary syphilis, treatment failure, HIV infection with late latent syphilis or syphilis of unknown duration, or serum nontreponemal titer ≥1:32, unless duration of infection is known to be <1 year 1, 2, 3, 5, 6
If CSF shows abnormalities consistent with neurosyphilis, the Centers for Disease Control and Prevention recommends treating as neurosyphilis with aqueous crystalline penicillin G 18-24 million units per day IV for 10-14 days 7

For non-pregnant patients with penicillin allergy, the Centers for Disease Control and Prevention recommends using alternative regimens only after CSF examination has excluded neurosyphilis, and using doxycycline 100 mg orally twice daily for 14 days or tetracycline 500 mg orally four times daily for 14 days for early latent syphilis, and doxycycline 100 mg orally twice daily for 28 days or tetracycline 500 mg orally four times daily for 28 days for late latent syphilis or unknown duration 1, 3, 5, 6, 7
The Centers for Disease Control and Prevention notes that pregnant patients allergic to penicillin must be desensitized and treated with penicillin, as there are no acceptable alternatives 1, 3, 5, 6, 7

The Centers for Disease Control and Prevention recommends repeating quantitative nontreponemal serologic tests at 6, 12, and 24 months after treatment, and re-treating the patient if titers increase fourfold, an initially high titer fails to decline at least fourfold within 12-24 months, or signs or symptoms attributable to syphilis develop 1, 3, 4, 5, 6

The American Academy of Pediatrics and the Centers for Disease Control and Prevention recommend that after the newborn period, children diagnosed with syphilis should have CSF examination to exclude neurosyphilis, and reviewing birth and maternal medical records to assess whether the child has congenital or acquired syphilis 1, 2, 3
For pediatric dosing, the Centers for Disease Control and Prevention recommends benzathine penicillin G 50,000 units/kg IM (up to adult dose of 2.4 million units) in a single dose for early latent syphilis, and benzathine penicillin G 50,000 units/kg IM (up to adult dose of 2.4 million units) administered as three doses at 1-week intervals (total 150,000 units/kg up to adult total dose of 7.2 million units) for late latent syphilis or unknown duration 1, 2, 3, 5, 6