Choose the drug which blocks basal as well as stimulated gastric acid secretion without affecting cholinergic, histaminergic or gastrin receptors
Omeprazole:- It is the prototype member of substituted benzimidazoles which inhibit the final common step in gastric acid secretion. The only significant pharmacological action of omeprazole is dose dependent suppression of gastric acid secretion; without anticholinergic or H2 blocking action. It is a powerful inhibitor of gastric acid: can totally abolish HCl secretion, both resting as well as that stimulated by food or any of the secretagogues, without much effect on pepsin, intrinsic factor, juice volume and gastric motility. Omeprazole is inactive at neutral pH, but at pH < 5 it rearranges to two charged cationic forms (a sulphenic acid and a sulphenamide configurations) that react covalently with SH groups of the H+K+ATPase enzyme and inacti- vate it irreversibly. Acid secretion resumes only when new H+K+ATPase molecules are synthesized (reactivation half time 18 hours). It also inhibits gastric mucosal carbonic anhydrase. Ref:- kd tripathi; pg num:-648,651,652
Loxatidine
Pirenzepine
Omeprazole
Famotidine
Gastrointestinal tract