n February 2015, vonoprazan was first marketed in Japan for the treatment of acid-related disorders and as an adjunct to Helicobacter pylori (H. pylori) eradication.¹ In May 2022, the FDA approved the use of vonoprazan in a co-packaged product containing amoxicillin and clarithromycin for the treatment of H. pylori infection. Studies have shown that the concomitant use of vonoprazan, amoxicillin, and clarithromycin leads to an H. pylori eradication rate of approximately 90%.

MOA– Vonoprazan is a potassium-competitive acid blocker (PCAB) that inhibits the H⁺, K⁺-ATPase enzyme system in a potassium-competitive manner. Through this mechanism, vonoprazan suppresses basal and stimulated gastric acid secretion at the secretory surface of gastric parietal cells.

Although both classes of drugs inhibit the H⁺, K⁺-ATPase, the mechanism of action of PCABs differs from that of proton-pump inhibitors (PPIs). PPIs form a covalent disulphide bond with a cysteine residue on the H⁺, K⁺-ATPase, which leads to the inactivation of the enzyme, while PCABs interfere with the binding of K⁺ to the H⁺, K⁺-ATPase.

1. Duration of Action:
   • One notable feature of vonoprazan is its longer duration of action compared to some traditional PPIs. This prolonged effect contributes to its effectiveness in maintaining acid suppression.
2. Pharmacokinetics:
   • Absorption: Vonoprazan is absorbed relatively quickly after oral administration, reaching peak plasma concentrations within a few hours.
   • Metabolism: It undergoes hepatic metabolism primarily through the cytochrome P450 enzyme system, specifically CYP3A4 and CYP2B6.
   • Excretion: The elimination half-life of vonoprazan is relatively long, contributing to its sustained therapeutic effect. The drug and its metabolites are primarily excreted in the feces.
3. Clinical Uses:
   • Vonoprazan is used in the management of various acid-related disorders, including gastroesophageal reflux disease (GERD), erosive esophagitis, and peptic ulcers.
   • It is often prescribed to promote healing of the esophagus and stomach lining and to relieve symptoms associated with excessive stomach acid.
4. Comparison with Other PPIs:
   • While vonoprazan shares the general mechanism of action with other PPIs, its irreversible binding to the proton pump may contribute to its prolonged duration of acid suppression compared to some traditional PPIs.
5. Considerations and Monitoring:
   • Healthcare professionals carefully consider individual patient factors, including liver function, potential drug interactions, and the specific acid-related disorder, when prescribing and monitoring vonoprazan.

INDICATION- Duodenal Ulcer, Erosive esophagitis, gastric ulcer, Heartburn

Common side effects of vonoprazan can include:

1. Headache: Some individuals may experience headaches as a side effect of vonoprazan.
2. Abdominal Pain: Pain or discomfort in the abdominal area is a reported side effect in some cases.
3. Nausea: Feeling nauseous or experiencing an upset stomach is another potential side effect.
4. Vomiting: Some individuals may experience vomiting as a side effect.
5. Diarrhea or Constipation: Changes in bowel habits, including diarrhea or constipation, can occur.
6. Flatulence: Increased gas production and flatulence may be observed.
7. Fatigue: Some people may feel tired or experience fatigue while taking vonoprazan.