Metsina 400 mg is an antibiotic belonging to the nitroimidazole class. It exhibits broad-spectrum activity against anaerobic bacteria and protozoa. After oral administration, it is rapidly and completely absorbed, with a plasma half-life of approximately 8 hours. The drug penetrates well into body tissues and fluids, and is primarily metabolized in the liver. Both unchanged metronidazole and its metabolites are excreted in the urine.