Gastrointestinal Drugs and Medications Q 13
Which of the following statements best describes the action of antacids?
A. Antacids neutralize gastric acid
B. Antacids block the production of gastric acid
C. Antacids block dopamine
D. Antacids enhance the action of acetylcholine
Correct Answer: A. Antacids neutralize gastric acid
Antacids act to bring the pH above 3. Antacids are a group of drugs that have been on the market for many years. They were initially first-line defense against peptic ulcer disease; however, the discovery of proton pump inhibitors revolutionized the treatment of peptic ulcer disease. Currently, antacid use is restricted to the relief of mild intermittent gastroesophageal reflux disease (GERD) associated with heartburn. Other choices are incorrect because they describe the actions of anti-acid drugs.
Option B: The antacids reduce the acid reaching the duodenum by neutralizing the acid present in the stomach. The salts’ mechanism of neutralization of acid varies, and each salt has a different mechanism with the ultimate goal of acid neutralization.
Option C: The formulation of aluminum hydrochloride and water results in the neutralization of the acid in the stomach. It is also known to inhibit pepsin activity. Aluminum hydroxide is complexed with a sulfated polysaccharide sucrose octasulfate to form sucralfate. This complex does not have a significant buffering action against the acid or has no effect on the pepsin secretion and does not alter the gastric acid production in any way. Nevertheless, it is known to heal chronic ulcers and prevent acute mucosal damage induced chemically by reducing access to pepsin and acid.
Option D: Calcium salts neutralize gastric acidity resulting in increased gastric and duodenal bulb pH; they additionally inhibit the proteolytic activity of pepsin if the pH is greater than 4 and increase lower esophageal sphincter tone. The calcium released from calcium carbonate is known to increase peristalsis in the esophagus, pushing the acid into the stomach and providing relief from symptoms of heartburn. The calcium salts also form combined insoluble compounds with dietary phosphate and prevent the absorption later.