night. A strong relationship has been stated between the degree and duration of gastric acid inhibition, as measured by monitoring of the 24-hour intragastric pH in pharmacodynamic studies, and the rate of healing and symptom relief reported. A clinical study showed that nocturnal acid breakthrough duration was significantly shorter for 40 mg of tenatoprazole than for 40 mg of esomeprazole, with the conclusion that tenatoprazole was significantly more potent than esomeprazole during the night. Although, the therapeutic relevance of this pharmacological advantage deserves further study. PPIs have been used successfully in triple-therapy regiments with clarithromycin and amoxicillin for the eradication of Helicobacter pylori with no significant difference between different PPI-based regimens. Future research and new generations of PPIs Potassium-competitive acid blockers or acid pump antagonists Despite the fact that PPIs have revolutionized the treatment of GERD, there is still room for improvement in the speed of onset of acid suppression as well as mode of action that is independent of an acidic environment and also better inhibition of the proton pump. Therefore, a new class of PPIs, potassium-competitive acid blockers (P-CABs) or acid pump antagonists (APAs), have been under development the past years and will most likely be the next generation of drugs that suppress gastric activity. These new agents can in a reversible and competitive fashion inhibit the final step in the gastric acid secretion with respect to K+ binding to the parietal cell gastric H+/K+ ATPase. That is, they block the action of the H+/K+ ATPase by binding to or near the site of the K+ channel. Since the binding is competitive and reversible these agents have the potential to achieve faster inhibition of acid secretion and longer duration of action compared to PPIs, resulting in quicker symptom relief and healing. The imidazopyridine-based compound SCH28080 was the prototype of this class, and turned out to be hepatotoxic. Newer agents that are currently in development include CS-526, linaprazan, soraprazan and revaprazan in which the latter have reached clinical trials. Studies remain to determine whether these or other related compounds can become useful. In June 2006, Yuhan obtained approval from the Korean FDA for the use of revaprazan (brand name Revanex) in the treatment of gastritis. Vonoprazan is marketed in Japan. See also Digestion Stomach Gastric acid Gastroesophageal reflux disease Hydrogen potassium ATPase Proton pump inhibitor References Proton-pump inhibitors Gastroenterology Proton-Pump Inhibitors, Discovery And Development Of