pantoprazole + amoxicillin + metronidazole + bismuth subcitrate

This is a four-drug combination regimen consisting of pantoprazole (a proton pump inhibitor), amoxicillin (a beta-lactam antibiotic), metronidazole (a nitroimidazole antibiotic), and bismuth subcitrate (a bismuth salt with antimicrobial and mucosal protective properties). The combination is used as a first-line or rescue therapy for the eradication of Helicobacter pylori infection, particularly in regions with high resistance to clarithromycin. Pantoprazole suppresses gastric acid secretion, creating an environment less favorable for H. pylori survival and enhancing the efficacy of antibiotics. Amoxicillin inhibits bacterial cell wall synthesis; metronidazole disrupts DNA structure through free radical formation; and bismuth subcitrate exerts direct bactericidal effects on H. pylori while also protecting the gastric mucosa[1][8]. This quadruple therapy has demonstrated high eradication rates, good tolerability, and is recommended in clinical guidelines for H. pylori management[8].