Which treatment is indicated for a patient with primary syphilis?

Benzathine penicillin G (Bicillin LA) is the first-line treatment recommended for primary syphilis. This formulation of penicillin is specifically effective against the bacteria Treponema pallidum, which causes syphilis. The intramuscular administration allows for sustained levels of the antibiotic in the bloodstream, effectively treating the infection.

In cases of primary syphilis, which is characterized by the presence of a painless chancre at the site of infection, early and effective treatment is crucial to prevent progression of the disease and to avoid transmission. Benzathine penicillin G not only resolves the infection but also helps in the potential prevention of serious complications associated with untreated syphilis.

Other treatment options listed may not provide the same efficacy or are not the recommended first-line therapies for primary syphilis. For instance, although doxycycline and azithromycin can be used in certain cases, they are not preferred over benzathine penicillin G, especially considering the well-established guidelines for syphilis treatment. Ceftriaxone, while it has some activity against Treponema pallidum, is also not the designated first-line treatment for this specific condition.