American Board of Internal Medicine (ABIM) Certification Practice Exam

Which treatment is recommended for secondary syphilis?

1. Benzathine penicillin

2. Doxycycline

3. Azythromycin

4. Ceftriaxone

The correct answer is: Benzathine penicillin

Benzathine penicillin is the recommended treatment for secondary syphilis because it is highly effective in eradicating the Treponema pallidum bacteria that cause the disease. The preferred dosage is typically a single intramuscular injection, which provides a sustained release of the antibiotic into the bloodstream, allowing it to act over an extended period. Secondary syphilis presents with a variety of systemic symptoms, including skin rashes and mucous membrane lesions. Benzathine penicillin has shown to be effective not only in resolving these symptoms but also in preventing further complications associated with untreated syphilis, such as tertiary syphilis and damage to multiple organ systems. While other antibiotics such as doxycycline, azithromycin, and ceftriaxone can be used in certain contexts—including for patients allergic to penicillin or in different stages of syphilis—Benzathine penicillin remains the gold standard for treating secondary syphilis due to extensive clinical evidence supporting its efficacy and safety profile.