Introduction
Cathartics, also known as laxatives, are substances that promote bowel movements and help relieve constipation.
They are used in the treatment of various gastrointestinal disorders, including constipation, irritable bowel syndrome (IBS), and bowel preparation for diagnostic procedures or surgeries.
Types of Cathartics:
1) Bulk-forming laxatives:
Mechanism: Increase the bulk and water content of the stool, making it easier to pass.
Examples: Psyllium husk, methylcellulose, calcium polycarbophil.
Uses: Treat constipation, especially in individuals with low-fiber diets or those who need to avoid straining during bowel movements.
2) Stool softeners:
Mechanism: Soften the stool by increasing its water content, facilitating easier passage.
Examples: Docusate sodium, docusate calcium.
Uses: Suitable for individuals recovering from surgery, childbirth, or those with hemorrhoids or anal fissures
3) Lubricant laxatives:
Mechanism: Coat the stool and intestinal lining, reducing friction and allowing for easier passage.
Examples: Mineral oil, liquid paraffin.
Uses: Provide short-term relief of constipation, particularly for those with difficulty passing hard stools..
4) Osmotic laxatives:
Mechanism: Draw water into the intestines, softening the stool and increasing intestinal motility.
Examples: Magnesium hydroxide, magnesium sulfate, lactulose, polyethylene glycol (PEG).
Uses: Treat constipation, prepare the bowel for diagnostic procedures or surgeries, and manage hepatic encephalopathy (lactulose)..
5) Stimulant laxatives:
Mechanism: Stimulate the intestinal muscles to contract, promoting bowel movements.
Examples: Senna, bisacodyl, castor oil.
Uses: Provide short-term relief of constipation, bowel preparation for procedures, and occasional use for constipation not responding to other treatments.
6) Prokinetic agents:
Mechanism: Increase gastrointestinal tract motility by acting on smooth muscles or nerves.
Examples: Metoclopramide, tegaserod.
Uses: Treat constipation associated with certain medical conditions (e.g., Parkinson's disease), gastroparesis, and irritable bowel syndrome with constipation (IBS-C).
This categorization helps in understanding the different mechanisms and appropriate uses of cathartics for various conditions.