Benzylpenicillin, also known as penicillin G, is a narrow-spectrum β-lactam antibiotic discovered from Penicillium species. It was one of the first antibiotics used successfully in clinical medicine. Benzylpenicillin works by inhibiting bacterial cell wall synthesis, leading to cell lysis and death. It is mainly effective against Gram-positive bacteria and some Gram-negative organisms. The drug is usually administered by intramuscular or intravenous injection due to poor oral stability. Benzylpenicillin is widely used in the treatment of streptococcal infections. It is also effective against syphilis caused by Treponema pallidum. The drug is used in treating infections such as pneumonia, meningitis, and endocarditis. It has a well-established safety profile but may cause allergic reactions in sensitive individuals. Benzylpenicillin remains an important and widely used antibiotic in clinical practice.
