Penicillin G benzathine, 2.4 million units IM as a single dose
Doxycycline, 100 mg PO twice daily for 14 d or ceftriaxone, 1-2 g either IM or IV daily for 10–14 d or tetracycline, 100 mg PO four times daily for 14 d
—
Late latent syphilis
Penicillin G benzathine, 2.4 million units IM once weekly for 3 wk
Doxycycline, 100 mg PO twice daily for 28 d or tetracycline, 100 mg PO four times daily for 28 d
—
Neurosyphilis
Penicillin G aqueous, 18–24 million units IV daily (3-4 million units q 4 h or by continuous infusion) for 10–14 d
Procaine penicillin, 2.4 million units IM daily plus probenecid, 500 mg PO four times daily, both for 10–14 d or ceftriaxone, 2 g either IM or IV daily for 10–14 d
Follow-up treatment with 3 additional weekly injections of penicillin G benzathine, 2.4 million units IM
Tertiary syphilis (not neurosyphilis)
Penicillin G benzathine, 2.4 million units IM once weekly for 3 wk
—
Cerebrospinal fluid evaluation should be performed before therapy