From the Guidelines
The treatment for a patient with a positive enzyme-linked immunosorbent assay (ELISA) for syphilis is penicillin G, with the specific regimen depending on the stage of infection. For primary, secondary, or early latent syphilis (less than one year duration), a single intramuscular injection of benzathine penicillin G 2.4 million units is recommended 1. This is based on the guidelines for prevention and treatment of opportunistic infections in HIV-infected adults and adolescents, which state that penicillin remains the treatment of choice for syphilis regardless of HIV status.
Key Considerations
- The stage of syphilis infection is crucial in determining the treatment regimen.
- For late latent syphilis (more than one year duration) or syphilis of unknown duration, the treatment consists of benzathine penicillin G 2.4 million units intramuscularly once weekly for three consecutive weeks.
- For neurosyphilis or ocular syphilis, aqueous crystalline penicillin G 3-4 million units intravenously every 4 hours for 10-14 days is the standard treatment.
- Patients with penicillin allergy can be treated with doxycycline 100 mg orally twice daily for 14 days (primary, secondary, early latent) or 28 days (late latent), though penicillin desensitization is preferred for pregnant women and neurosyphilis cases 1.
Follow-up and Confirmation
It's essential to note that a positive ELISA alone is not diagnostic for syphilis and should be confirmed with a treponemal-specific test. Follow-up serologic testing at 6 and 12 months is crucial to ensure treatment success 1. Penicillin is highly effective against Treponema pallidum (the causative organism) because it disrupts cell wall synthesis during bacterial replication, and its long-acting formulation maintains therapeutic levels for extended periods.
Treatment Failure and Neurologic Complications
HIV-infected persons with early-stage syphilis should receive a single intramuscular (IM) injection of 2.4 million units of benzathine penicillin G, and some specialists recommend two additional weekly benzathine penicillin injections, although the benefit of this treatment approach remains unproven 1. Retreatment of persons with early-stage syphilis should be considered for those who have a sustained fourfold increase in serum nontreponemal titers after an initial reduction after treatment, or have persistent or recurring clinical signs or symptoms of disease 1.
From the FDA Drug Label
All cases of penicillin treated syphilis should receive adequate follow-up including clinical and serological examinations. Patients being treated for gonococcal infection should have a serologic test for syphilis before receiving penicillin.
The treatment for a patient with a positive enzyme-linked immunosorbent assay (ELISA) for syphilis is penicillin G.
- The patient should receive adequate follow-up including clinical and serological examinations.
- Penicillin G is the recommended treatment, and the patient should be counseled to take the medication exactly as directed. 2
From the Research
Treatment for Syphilis
The treatment for a patient with a positive enzyme-linked immunosorbent assay (ELISA) for syphilis depends on the stage of the disease.
- For early syphilis, the preferred treatment is a single dose of 2.4 million units of benzathine penicillin G 3.
- Doxycycline is recommended as a second-line treatment for early syphilis, with a dosage of 100 mg orally, twice daily for 14 days 4, 5.
- Studies have shown that doxycycline is an effective agent for the treatment of early syphilis, with serological response rates similar to those of benzathine penicillin G 4, 5, 6.
- In HIV-infected patients, the serological response rates to doxycycline and benzathine penicillin G were also similar 6.
Serological Response
The serological response to treatment is an important indicator of the effectiveness of the treatment.
- A decline of rapid plasma reagin titer by 4-fold or greater at 6 and 12 months of treatment is considered a successful serological response 6.
- Studies have shown that the serological response rates to doxycycline and benzathine penicillin G are similar, with no statistically significant differences at 6 and 12 months of treatment 5, 6, 7.
Special Considerations
In certain cases, special considerations need to be taken into account when treating syphilis.