amoxicillin + metronidazole + bismuth

This drug is a combination of three active pharmaceutical ingredients—amoxicillin, metronidazole, and bismuth—used primarily as part of multi-drug regimens for the eradication of Helicobacter pylori infection. Amoxicillin is a beta-lactam antibiotic that inhibits bacterial cell wall synthesis. Metronidazole is a nitroimidazole antibiotic effective against anaerobic bacteria and certain protozoa by disrupting DNA synthesis. Bismuth compounds have antimicrobial activity against H. pylori and also provide mucosal protection in the gastrointestinal tract. This combination may be used with or without additional agents (such as proton pump inhibitors) in modified quadruple therapy regimens to overcome resistance to other antibiotics and improve eradication rates for H. pylori-associated peptic ulcer disease[2][7].