Omilock Capsule Mechanism of Action

Pharmacology: Pharmacodynamics: Mode or Mechanism of Action: Omeprazole is activated at an acidic pH to a sulphenamide derivative that binds irreversibly to H⁺, K⁺-ATPase, an enzyme system found at the secretory surface of parietal cells. It thereby inhibits the final transport of hydrogen ions (via exchange with potassium ions) into the gastric lumen. Since the H⁺, K⁺-ATPase enzyme system is regarded as the acid (proton) pump of the gastric mucosa, omeprazole is known as a gastric acid pump inhibitor. Omeprazole inhibits both basal and stimulated acid secretion irrespective of the stimulus.
Omeprazole has cytoprotective effects in rats, protecting the gastric mucosa from the effects of gastric irritants. This protective effect does not seem to be prostaglandin mediated.
Pharmacokinetics: Absorption: Rapid; 50 - 65%.
Distribution: Distributed in tissue, particularly gastric parietal cells.
Protein binding: Very high, approximately 95% bound to albumin and alpha₁-acid glycoprotein.
Biotransformation: Hepatic, extensive.
Half-life: Plasma: Normal hepatic function - 30 minutes to 1 hour.
Chronic hepatic disease - 3 hours.
Onset of action: Within one hour.
Time to peak concentration: Within 30 minutes to 3.5 hours.
Time to peak effect: Within 2 hours.
Duration of action: Up to 72 hours or more (96 hours required for full restoration of acid production).
Elimination: Renal - 72 to 80%.
Fecal - 18 to 23%.
ln dialysis - Not readily dialyzable, because of extensive protein binding.
Pharmacogenetics: Pharmacokinetic studies in Asian subjects receiving single 20-mg doses of omeprazole showed an approximately fourfold increase in the area under the plasma concentration-time curve (AUC) as compared to Caucasian subjects.
Dosage adjustments should be considered for Asian patients, especially for prophylaxis of recurrence of erosive esophagitis.