What is the standard treatment for a patient diagnosed with syphilis?

The standard treatment for syphilis is Benzathine penicillin G. This medication is a long-acting form of penicillin that is effective against Treponema pallidum, the bacterium responsible for syphilis. The mechanism of action involves inhibiting bacterial cell wall synthesis, which is crucial for the survival of the bacteria.

Administering Benzathine penicillin G helps to effectively clear the infection, preventing potential complications associated with untreated syphilis, such as neurological and cardiovascular issues. The treatment is typically a one-time intramuscular injection for early syphilis, while patients with late latent syphilis may require additional doses.

The other medications listed serve different purposes. Valacyclovir is an antiviral used primarily for herpes simplex virus infections, not bacterial infections like syphilis. Ceftriaxone is a broad-spectrum cephalosporin antibiotic often used for bacterial infections but is not the standard treatment for syphilis. Metronidazole is an antibiotic effective for anaerobic bacteria and protozoan infections, such as bacterial vaginosis and trichomoniasis, but it does not have efficacy against Treponema pallidum. Thus, Benzathine penicillin G is specifically chosen due to