Latent Syphilis
ICD-10 A53.0 · ICD-11 1A63

Early Latent Syphilis: Second-Line Treatment When Benzathine Penicillin G Is Not Available

This protocol covers early latent syphilis acquired within the past year, in patients with no penicillin allergy and no bleeding disorder, when the first-line regimen cannot be administered.

Clinical Scenario

Early latent syphilis is classified as infection acquired within the first year. This scenario applies to patients with confirmed early latent infection (acquired <1 year previously), no penicillin allergy, and no bleeding disorder.

First-Line Reference

First-Line Regimen: Benzathine Penicillin G (BPG)

The established first-line treatment for this presentation is Benzathine penicillin G. The target for that regimen is a sufficient decline in non-treponemal antibody titre (VDRL/RPR) within six months. When BPG is not available, this second-line protocol applies.

Second-Line Approach (Partial Overview)

When BPG is not available, a procaine penicillin-based regimen is used as second-line therapy for this population. The complete regimen — including schedule, duration, and all clinical decision criteria — is contained in the full protocol.

Treatment Target

After treatment, the titre of a non-treponemal test (VDRL/RPR) taken at day 0 should decline by at least two dilution steps — a fourfold decrease in antibody titre — within six months.

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References

DOI: 10.1111/jdv.16946

Rather arbitrarily classified as early if within the first year of infection and late (or undetermined duration) after ≥1 year.

Early syphilis (Primary, Secondary and Early latent, i.e. acquired <1 year previously)

Procaine penicillin 600 000 units IM daily for 10–14 days, i.e. if BPG is not available

After treatment of early syphilis, the titre of a NTT taken at day 0 (e.g. VDRL and/or RPR) should decline by ≥2 dilution steps (≥fourfold decrease in titre of antibodies) within 6 months.

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