vonoprazan + doxycycline

Vonoprazan + doxycycline is a combination therapy used primarily for Helicobacter pylori eradication, especially in patients with penicillin allergy. Vonoprazan is a potassium-competitive acid blocker (PCAB) that inhibits H+/K+-ATPase in a noncovalent and reversible manner, blocking potassium binding through competitive inhibition. This mechanism causes rapid, profound, and sustained suppression of gastric acid secretion, resulting in elevated intragastric pH. Doxycycline is a tetracycline antibiotic that inhibits bacterial protein synthesis. The combination is often used with other agents like bismuth and metronidazole in quadruple therapy regimens for H. pylori eradication.