From the Guidelines
Osmotic laxatives are a type of medication that draws water into the gut to hydrate the stool, making it easier to pass.
Key Characteristics of Osmotic Laxatives
- They work by increasing the amount of water in the large bowel, either by drawing fluid from the body into the bowel or by retaining the fluid that was administered 1
- Examples of osmotic laxatives include:
- Polyethylene glycol (PEG): an inert polymer of ethylene glycol that sequesters fluid in the bowel 1
- Lactulose: a semi-synthetic disaccharide that is not absorbed from the gastrointestinal tract and produces osmotic diarrhea of low pH 1
- Magnesium salts: useful where rapid bowel evacuation is required, but should be used with caution in patients with renal insufficiency and in pregnancy 1
Mechanism of Action and Guidance for Use
- Osmotic laxatives increase the amount of water in the large bowel, making the stool softer and easier to pass 1
- They are recommended for the treatment of chronic idiopathic constipation and can be used in combination with other medications if needed 1
- The dose of osmotic laxatives may be adjusted based on symptom response and side effects, and there is no clear maximum dose for most of these medications 1
From the Research
Definition of Osmotic Laxatives
- Osmotic laxatives are a type of laxative that works by holding water inside the bowel lumen 2
- They are commonly used to treat chronic constipation and are considered effective and safe treatments 3, 4, 5, 6
Examples of Osmotic Laxatives
- Lactulose is an example of an osmotic laxative 3, 5
- Polyethylene Glycol (PEG) is another example of an osmotic laxative 3, 5, 6
- Magnesium and phosphate containing laxatives are also osmotic laxatives 4
Mechanism of Action
- Osmotic laxatives work by drawing water into the bowel lumen, softening the stool and making it easier to pass 2
- They can also stimulate bowel movements by increasing the amount of water in the stool 4