Magnesium Hydroxide/Omeprazole/Sodium Bicarbonate

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 (Cmax) and a significantly shorter mean time to reach Cmax (tmax) 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.

Immediate-release omeprazole (Zegerid, Santarus) is the first immediate-release oral proton pump inhibitor to reach the market. As a powder formulation for oral suspension, it is indicated for the treatment of gastroesophageal reflux disease, erosive oesophagitis, duodenal ulcer and gastric ulcer, and is the only proton pump inhibitor approved for the reduction of risk of upper gastrointestinal bleeding in critically ill patients. Administration of immediate-release omeprazole at bedtime results in a rapid and sustained elevation of gastric pH, and seems to provide better night time control of gastric acidity than that observed with conventional morning dosing of delayed-release proton pump inhibitors. The immediate-release formulation may provide a good treatment option for patients who require flexible dosing, quick onset of action and nocturnal gastric acid control.