antibacterial (trade name Dynapen) used to treat staphylococcal infections that are resistant to penicillin
A narrow-spectrum beta-lactam antibiotic of the penicillin class, used in the form of its hydrated sodium salt C₁₉H₁₆Cl₂N₃NaO₅S·H₂O especially against beta-lactamase producing staphylococci.