Drug Groups

approved; investigational

Description

A highly effective inhibitor of gastric acid secretion used in the therapy of stomach ulcers and zollinger-ellison syndrome. The drug inhibits the H(+)-K(+)-ATPase (H(+)-K(+)-exchanging ATPase) in the proton pump of gastric parietal cells. [PubChem]

Indication

For the treatment of acid-reflux disorders (GERD), peptic ulcer disease, H. pylori eradication, and prevention of gastroinetestinal bleeds with NSAID use.

Pharmacology

Omeprazole is a compound that inhibits gastric acid secretion and is indicated in the treatment of gastroesophageal reflux disease (GERD), the healing of erosive esophagitis, and H. pylori eradication to reduce the risk of duodenal ulcer recurrence. Omeprazole belongs to a new class of antisecretory compounds, the substituted benzimidazoles, that do not exhibit anticholinergic or H2 histamine antagonistic properties, but that suppress gastric acid secretion by specific inhibition of the H⁺/K⁺ ATPase at the secretory surface of the gastric parietal cell. As a result, it inhibits acid secretion into the gastric lumen. This effect is dose-related and leads to inhibition of both basal and stimulated acid secretion irrespective of the stimulus.

Toxicity

Symptoms of overdose include confusion, drowsiness, blurred vision, tachycardia, nausea, diaphoresis, flushing, headache, and dry mouth.

Affected Organisms

Biotransformation

Hepatic.

Absorption

Absorption is rapid, absolute bioavailability (compared to intravenous administration) is about 30-40% at doses of 20-40 mg.

Half Life

0.5-1 hour

Protein Binding

95%

Elimination

Urinary excretion is a primary route of excretion of omeprazole metabolites.

Clearance

* total body cl=500-600 mL/min [healthy]
* 250 mL/min [Geriatric]
* 70 mL/min [Hepatic Impairment]
* 10 - 62 mL/min/1.73 m2 [Renal Impairment]

References

External Links