These agents decrease intestinal muscle tone to slow passage of feces?

AIIMS Nagpur NO- 2020

Pharmacology

Easy

Appeared in: AIIMS Nagpur NO- 2020

Explanation

Antidiarrheal opiate agents, such as loperamide and diphenoxylate, act directly on opioid receptors located in the wall of the intestine.
This action inhibits the propulsive, wave-like muscle contractions (peristalsis) and reduces the overall tone of the intestinal smooth muscle.
By slowing down the movement of contents through the gut, these agents increase the transit time.
A longer transit time allows for more extensive absorption of water and electrolytes from the fecal matter back into the body.
This results in firmer stools and a reduction in the frequency of bowel movements, effectively treating diarrhea.

Option A: Hypertonic solutions are osmotic agents. They work by drawing a large amount of water into the colon, which increases the volume of stool, stretches the bowel wall, and stimulates peristalsis to promote defecation.
Option B: Cathartics are potent stimulant laxatives that induce a rapid and strong propulsive action in the intestines, accelerating the passage of feces for a complete bowel evacuation.
Option C: Laxatives are a broad category of medications used to treat constipation. Their primary function is to promote or facilitate bowel movements, which is the opposite of slowing the passage of feces.

Clinical Relevance

Nursing practice connection: This is primarily an exam-oriented knowledge point with limited direct bedside application, so retain Pharmacology of Bowel Disorder Drugs as background academic context rather than a clinical decision trigger.
A critical nursing responsibility is to assess the cause of diarrhea before administering an antidiarrheal. These agents are contraindicated in diarrhea caused by infections like C. difficile or E. coli, as slowing gut motility can trap the pathogen and its toxins, potentially leading to severe complications like toxic megacolon.
Nurses must monitor patients for adverse effects, including constipation, abdominal cramping, drowsiness, and dizziness. For agents like diphenoxylate/atropine, anticholinergic effects (dry mouth, urinary retention) should also be assessed.
What if? If a patient with diarrhea is also taking a CNS depressant, the nurse should use opiate antidiarrheals with extreme caution and monitor for excessive sedation, as their effects can be additive.

How to Approach the Question

First, identify the core physiological action described in the question: 'decrease intestinal muscle tone to slow passage of feces'.
Recognize that this action is intended to treat diarrhea by reducing gut motility.
Evaluate each option's primary mechanism. 'Hypertonic' solutions, 'Cathartics', and 'Laxatives' are all used to treat constipation by stimulating or speeding up bowel movements.
Eliminate the first three options because their function is the opposite of what the question describes.
Identify 'Antidiarrheal opiate agents' as the only class specifically designed to reduce intestinal motility and slow fecal transit, directly matching the described action.

Concept Tested & Keywords

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