Tenatoprazole (rINN, also benatoprazole) is a novel proton pump inhibitor indicated for the treatment of reflux oesophagitis and peptic ulcer in Japan. Discovered by Mitsubishi Pharma, it is an imidazopyridine derivative and has an imidazopyridine ring in place of the benzimidazole moiety found in other proton pump inhibitors. It is activated more slowly than other proton pump inhibitors but its inhibition is resistant to reversal. Tenatoprazole has an extended plasma half-life in comparison with all other proton pump inhibitors; this makes it more potent and effective in the treatment of nocturnal acid breakthrough than esomeprazole, one of the most popular proton pump inhibitors.