Laxatives are substances or medications that promote bowel movements and relieve constipation by increasing the frequency and ease of stool passage.
Classification of Laxatives
1. Bulk-forming laxatives
Bulk-forming laxatives are a type of laxative that promotes bowel movements by adding bulk and moisture to the stool, facilitating its passage through the intestines. These laxatives are often used to treat constipation and promote regular bowel movements.
Examples: Psyllium, methylcellulose.
Mechanism: Increase fecal mass and soften stools, promoting bowel movements.
2. Stool softeners/emollient laxatives
Stool softeners, also known as emollient laxatives, are substances or medications that help prevent and relieve constipation by mixing water and fats into the stool, making it softer and easier to pass.
Example: Docusate sodium.
Mechanism: Allow water and fats to penetrate and soften the stool.
3. Osmotic laxatives
Osmotic laxatives are substances or medications that promote bowel movements by drawing water into the intestines, softening the stool, and stimulating bowel movements.
Examples: Polyethylene glycol lactulose.
Mechanism: Draw water into the bowel, softening the stool and promoting bowel movements.
4. Stimulant laxatives
Stimulant laxatives are a class of medications that promote bowel movements by directly irritating the mucosa of the intestines. This irritation leads to increased contractions of the smooth muscles in the intestines, facilitating the passage of stool. Stimulant laxatives are commonly used to provide prompt relief from constipation and to prepare the bowel for certain medical procedures. Examples include substances like senna and medications like bisacodyl. It’s important to use stimulant laxatives under the guidance of a healthcare professional due to the potential for side effects and dependence with prolonged use.
Examples: Senna, bisacodyl.
Mechanism: Directly stimulate intestinal muscles, promoting bowel contractions.
5. Saline laxatives
Saline laxatives are a type of laxative that promotes bowel movements by increasing water retention in the intestines, leading to stool softening and stimulating bowel movements.
Example: Magnesium citrate.
Mechanism: Increase water retention in the bowel, softening the stool and stimulating bowel movements.
Pharmacological Actions of Laxatives
– Bulk-forming laxatives add mass to the stool, promoting peristalsis.
– Stool softeners/emollient laxatives soften stools by facilitating water and fat penetration.
– Osmotic laxatives draw water into the bowel, softening the stool and promoting bowel movements.
– Stimulant laxatives directly stimulate intestinal muscles, enhancing peristalsis.
– Saline laxatives increase water retention in the bowel, promoting bowel movements.
Dose of Laxatives
– Dosage varies depending on the specific laxative and the patient’s condition.
– It is crucial to follow healthcare provider recommendations and product guidelines.
Indications
– Constipation.
– Preoperative and postoperative bowel preparation.
– Conditions requiring easy bowel movements (e.g., hemorrhoids, anal fissures).
– Diagnostic and therapeutic procedures requiring clear intestines.
Contraindications
– Known allergy or hypersensitivity to specific laxatives.
– Bowel obstruction.
– Acute abdominal pain.
– Severe dehydration.
– Inflammatory bowel diseases (use with caution).
Laxatives should be used with caution and under medical supervision, as misuse or overuse can lead to electrolyte imbalances, dehydration, and other complications. Individuals need to consult healthcare professionals before starting any laxative regimen.
