salvarsan

Salvarsan, also known as arsphenamine or by its trade name Salvarsan, was the first systemic antimicrobial agent used to treat syphilis. It is an organoarsenic compound discovered as part of Paul Ehrlich's search for a "magic bullet" and introduced with Sahachiro Hata in 1909–1910. The compound, later referred to as the 606th in Ehrlich's series, demonstrated activity against Treponema pallidum, the bacterium that causes syphilis, and became the standard therapy for several decades.

Chemically, arsphenamine is an arsenic-containing organic compound. Its therapeutic effect is thought to arise from interference with bacterial enzymes, particularly those involving sulfhydryl groups, thereby inhibiting replication of the organism. The exact mechanism in Treponema pallidum is complex and not wholly understood.

Administration of Salvarsan was by deep intramuscular injection in hospital settings. Treatment regimens typically spanned weeks and required multiple injections, with careful monitoring for toxicity. Because of its arsenic content, adverse effects were common and could be severe, including fever, rash, anemia, nephrotoxicity, and other signs of arsenic poisoning.

Legacy: Salvarsan represented a major milestone in antimicrobial therapy. It remained the standard systemic therapy for syphilis until penicillin became widely available in the 1940s, offering higher efficacy and far lower toxicity. Today, Salvarsan is viewed primarily as a historical example of early antibiotic development.