From the Guidelines
Treatment for a positive Rapid Plasma Reagin (RPR) test involves penicillin G as the first-line therapy, with the specific regimen depending on the stage of syphilis. For primary, secondary, or early latent syphilis (less than one year), a single intramuscular injection of benzathine penicillin G 2.4 million units is recommended 1. For late latent syphilis (more than one year) or syphilis of unknown duration, three weekly doses of benzathine penicillin G 2.4 million units are needed. Neurosyphilis requires a more intensive approach with aqueous crystalline penicillin G 18-24 million units daily, administered as 3-4 million units IV every 4 hours for 10-14 days.
Key Considerations
- For penicillin-allergic patients, doxycycline 100 mg orally twice daily for 14 days (early syphilis) or 28 days (late syphilis) is an alternative, though desensitization to penicillin is preferred for pregnant women 1.
- Follow-up RPR testing is essential at 6,12, and 24 months to confirm treatment success, indicated by a fourfold decrease in titer.
- Sexual partners from the past 90 days should be notified, tested, and treated presumptively.
- Penicillin remains highly effective against Treponema pallidum because the spirochete has not developed resistance, and its long-acting formulation maintains therapeutic levels needed to eliminate the slowly dividing organism.
Special Populations
- Pregnant women should be screened serologically for syphilis early in pregnancy, and those with reactive treponemal screening tests should have confirmatory testing with nontreponemal tests with titers 1.
- In populations with high prevalence of syphilis or for patients at high risk, serologic testing should be performed twice during the third trimester and at delivery.
From the FDA Drug Label
Syphilis (neurosyphilis) 12 to 24 million units/day, as 2-4 MU every 4 hours for 10-14 days; many experts recommend additional therapy with Benzathine PCN G 2. 4 MU IM weekly for 3 doses after completion of IV therapy
- The treatment for a patient with a positive Rapid Plasma Reagin (RPR) test is penicillin G (IM).
- The recommended dosage for syphilis (neurosyphilis) is 12 to 24 million units/day, administered as 2-4 MU every 4 hours for 10-14 days.
- Additional therapy with Benzathine PCN G 2.4 MU IM may be recommended weekly for 3 doses after completion of IV therapy 2.
From the Research
Treatment for Positive RPR
The treatment for a patient with a positive Rapid Plasma Reagin (RPR) test, which is indicative of syphilis, depends on the stage of the disease and the patient's overall health.
- Benzathine penicillin G is the recommended treatment for early syphilis in non-penicillin-allergic patients 3, 4, 5, 6.
- For patients who are allergic to penicillin, doxycycline or tetracycline can be used as alternative treatments 4, 5, 6.
- The dosage and duration of treatment may vary depending on the stage of the disease and the patient's response to treatment.
Treatment Options
- Benzathine penicillin G: 2.4 million units given intramuscularly weekly for two weeks for a total of 4.8 million units 6.
- Doxycycline: 100 mg orally, twice daily for 14 days 4, 5.
- Tetracycline: 500 mg orally, four times daily for 12-14 days 5, 6.
- Azithromycin: 2.0 g orally, as a single dose or as two doses 1 week apart 3.