Antiulcerant — IY-81149
The treatment of peptic ulcers was revolutionised by the introduction of the histamine H2 receptor antagonists, of which cimetidine was the first. These were followed by the proton pump inhibitors, notably omeprazole, which act at a later stage of gastric acid release as they inhibit the enzyme H+K+ATPase. This means they have a more selective action, and are of particular value in the treatment of gastric ulcers that prove resistant to other forms of therapy.
A new proton pump inhibitor that is under investivation is IY-81149. Clinical trials have shown it to have improved pharmacological properties, in particular the fact that it does not cause an increase in blood gastrin concentration, unlike omeprazole.
Most notably, however, it has been found to have a bactericidal effect on Helicobacter pylori, the bacterium implicated in most ulcers, around 2–4 times stronger than omeprazole. It has been found to be effective in doses of 10mg/day, compared to doses of 20mg for omeprazole, 30mg for lansoprazole, and 40mg for pantoprazole.
In a comparative study with omeprazole,1 patients received 5, 10 or 20mg/day IY-81149 or 20mg/day omeprazole in a crossover fashion, with a 14 day washout period between the two treatments. The two higher doses of IY-81149 showed significantlly greater efficacy at suppressing gastric acid secretion, as assessed by the median gastric pH over a 24hr period.
Its high potency and relatively long-lasting antisecretory action compared to omeprazole mean it could prove to be an excellent long-acting drug for the treatment of peptic ulcer.