PCABs (Acid Blockers)

Potassium-competitive acid blockers (PCABs, also written P-CABs) are the newest class of acid suppressants, working by reversibly competing with potassium ions at the H+/K+ ATPase pump in gastric parietal cells. Unlike proton pump inhibitors (PPIs), PCABs do not require activation by acid, do not require dosing before meals, and have a faster, more potent, and more sustained acid-suppressive effect.

Vonoprazan is the most widely studied PCAB, approved in Japan since 2014 and in the US for erosive esophagitis and H. pylori eradication regimens. Tegoprazan and revaprazan are additional PCABs available in parts of Asia. Compared with PPIs, vonoprazan achieves higher and more sustained intragastric pH elevation, particularly at night, and shows superior healing rates for severe (LA Grade C/D) erosive esophagitis. In H. pylori eradication, vonoprazan-based dual or triple regimens consistently outperform PPI-based triple therapy in regions with high clarithromycin resistance.

Open clinical questions include the long-term safety profile (gastrin elevation is more pronounced than with PPIs, with theoretical implications for fundic gland polyps and enterochromaffin-like cell hyperplasia), the role in non-erosive reflux disease, and cost-effectiveness against generic PPIs in resource-limited settings.