title: Review article: immediate-release proton-pump inhibitor therapy--potential advantages.
abstract: The absorption of most oral proton-pump inhibitors is delayed by the enteric coating required to protect the acid-labile proton-pump inhibitor from degradation in the stomach and, as a result, antisecretory effect is also delayed. This article provides an overview of the pharmacokinetics and pharmacodynamics of a new immediate-release omeprazole [(IR-OME) Zegerid power for oral suspension; Santarus Inc., San Diego, CA, USA] and its potential advantages over delayed-release proton-pump inhibitors. Immediate-release omeprazole has a higher mean peak plasma omeprazole concentration (C(max)) and a significantly shorter mean time to reach C(max) (t(max)) than delayed-release omeprazole. Immediate-release omeprazole 40 mg has a prolonged antisecretory effect with median intragastric pH above 4.0 for 18.6 h/day at steady-state, after 7 days of once daily dosing. The sodium bicarbonate in immediate-release omeprazole protects the uncoated omeprazole from degradation by gastric acid. The accelerated antisecretory action of immediate-release omeprazole compared with delayed-release omeprazole may be due to the activation of proton pumps by the rapid neutralization of intragastric acid by the sodium bicarbonate. The faster onset of action seen with immediate-release omeprazole is not achieved by using an antacid with a delayed-release proton-pump inhibitor, because administering antacids with conventional delayed-release proton-pump inhibitors does not significantly enhance absorption of the proton-pump inhibitor. In conclusion, immediate-release omeprazole is associated with rapid absorption of omeprazole and rapid onset of antisecretory effect, without compromising the duration of acid suppression.
authors.affiliation: Division of Gastroenterology, Northwestern University Feinberg School of Medicine, Chicago, IL, USA. c-howden@northwestern.edu
authors.forename: C W
authors.initials: CW
authors.lastname: Howden
mesh_terms: D003692:Delayed-Action Preparations / Q000493:pharmacokinetics / Q000494:pharmacology / Q000627:therapeutic use; D004791:Enzyme Inhibitors / Q000493:pharmacokinetics / Q000494:pharmacology / Q000627:therapeutic use*; D005764:Gastroesophageal Reflux / Q000188:drug therapy*; D006801:Humans; D009853:Omeprazole / Q000493:pharmacokinetics / Q000494:pharmacology / Q000627:therapeutic use*; D054328:Proton Pump Inhibitors; D016896:Treatment Outcome
chemical_list: D003692:Delayed-Action Preparations; D004791:Enzyme Inhibitors; D054328:Proton Pump Inhibitors; D009853:Omeprazole