Gastrointestinal System 1 out of 480
A 33-year-old man comes to the physician because of a 2-month history of burning epigastric pain, dry cough, and occasional regurgitation. The pain is aggravated by eating and lying down. Physical examination shows a soft, non-tender abdomen. Upper endoscopy shows hyperemia in the distal third of the esophagus. Which of the following drugs is most likely to directly inhibit the common pathway of gastric acid secretion?
Aluminum hydroxide
Antacids such as aluminum hydroxide are used for symptomatic relief in mild, intermittent GERD as they directly neutralize gastric acid. However, antacids do not affect gastric acid secretion.
Lansoprazole
Proton pump inhibitors (PPIs) like lansoprazole are the first-line treatment for moderate to severe GERD. PPIs directly inhibit the H+/K+ ATPase, making them the most effective agents for the treatment of GERD.
Pirenzepine
Anticholinergics such as pirenzepine reduce gastric acid secretion by blocking acetylcholine-mediated gastric secretion. However, anticholinergics do not block acid secretion stimulated via other routes, such as gastrin or histamine. Ranitidine
H2 receptor blockers such as ranitidine may be used for mild GERD symptoms as they inhibit histamine-dependent gastric acid secretion by antagonizing H2 receptors in gastric parietal cells. However, they do not block acid secretion stimulated via other routes, such as gastrin or acetylcholine.
Sucralfate
Sucralfate is used as an adjunct treatment for peptic ulcer disease as it enhances the mucosal barrier in particularly acidic areas of the stomach and duodenum, acting as an acid buffer and promoting HCO3- production. However, sucralfate does not affect gastric acid secretion. Octreotide
Octreotide, a somatostatin analog, is used in the management of gastric acid secretion secondary to hypergastrinemia (e.g, Zollinger- Ellison syndrome). Octreotide significantly reduces gastrin secretion, which decreases gastric acid secretion. However, it does not block acid secretion stimulated via other routes, such as histamine and acetylcholine.
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