Match the laxative with its associated mechanism of action. A. Draws water into the intestine to relieve constipation B. Softens and increases bulk of digested food C. Increases water in stools to soften it so it is more comfortable to pass D. Activates chloride channels to enhance intestinal fluid secretion Options: 1. Lubiprostone _ 2. Psyllium _ 3. Polyethylene glycol _ 4. Mineral oil _
The Correct Answer and Explanation is:
Here is the correct matching of the laxatives with their mechanisms of action:
- Lubiprostone — D. Activates chloride channels to enhance intestinal fluid secretion
- Psyllium — B. Softens and increases bulk of digested food
- Polyethylene glycol — A. Draws water into the intestine to relieve constipation
- Mineral oil — C. Increases water in stools to soften it so it is more comfortable to pass
Detailed Explanation (300+ words):
Laxatives are substances used to treat constipation by promoting bowel movements. Each class of laxative works through a different mechanism, and it’s important for nurses and other healthcare providers to understand these mechanisms to provide safe, effective, and individualized care.
- Lubiprostone (D) is a chloride channel activator. It acts by directly stimulating the type-2 chloride channels (ClC-2) on the apical membrane of intestinal epithelial cells. This increases the secretion of chloride-rich fluid into the intestinal lumen, which enhances motility and softens the stool. It is particularly effective in treating chronic idiopathic constipation and irritable bowel syndrome with constipation (IBS-C).
- Psyllium (B) is a bulk-forming laxative derived from the husks of Plantago seeds. It works by absorbing water in the intestine, forming a bulky, soft stool mass that stimulates peristalsis. It mimics the action of dietary fiber, making it ideal for patients who need a long-term, gentle way to manage constipation. It is especially useful in patients with chronic constipation or irregular bowel habits.
- Polyethylene glycol (PEG) (A) is an osmotic laxative. It works by retaining water in the stool through osmotic action, thereby increasing the water content in the intestines. This softens stools and stimulates bowel movements. It is non-absorbable and is commonly used for bowel preparation before procedures like colonoscopy or for occasional constipation relief.
- Mineral oil (C) is a lubricant laxative. It coats the stool and the bowel wall with a waterproof film, which helps retain moisture in the stool and eases its passage. While effective in the short term, long-term use is not recommended due to potential complications such as lipid pneumonia if aspirated.
Understanding each laxative’s action helps guide their safe and appropriate use in clinical practice.