Laxatives are commonly used medications for treating occasional constipation. They are available over the counter (OTC) and based on how they work, they can be categorized into osmotic agents, stimulants, bulk-forming agents, and stool softeners.
Agents such as polyethylene glycol (PEG), lactulose, and magnesium hydroxide are water-loving substances that attract and retain water in the colon to ease and enhance stool passage Polyethylene glycol (found in RestoraLAX®) increases stool frequency and softness in individuals with constipation. It works with the water in your body to hydrate and soften stool, unblocking your bowel.
This type of laxative makes your body go by directly stimulating the nerves in your colon. This causes the muscles of the intestinal wall to contract and helps to push the stool along. This action can be effective for relieving occasional constipation. Senna and Bisacodyl are the most commonly used stimulant laxatives and are found in brands such as Senokot®, Ex-Lax®, and Dulcolax®.
Bulk-forming agents are fibre supplements that trap water in the stool to increase stool weight and improve stool consistency. Commercially available fibre supplements include psyllium and bran. They may be appropriate for people who do not consume enough fibre in their diet. Some powder fibre supplements can be gritty and viscous when mixed into a beverage, which some people may find distasteful. Adequate fluid intake is necessary for bulk-forming agents to work; lack of water may enhance bloating. Bulk-forming brands include Benefibre® and Metamucil®.
As the name suggests, stool softeners, such as docusate sodium, moisten and soften stool, making it easier to pass. They may work well for people with hard stools. Stool softener brands include Colace®.
|Osmotic Laxative‡*||Bulk-Forming (Fibre) Laxative*||Stimulant Laxative†|
|Example of Brands||RestoraLAX®, Phillips Milk of Magnesia||Metamucil®, Fibre ChoiceTM||Senokot®, Ex-lax®, Dulcolax®|
|Examples of Medical Ingredients||Polyethylene glycol, Magnesium hydroxide||Psyllium, Inulin||Sennosides, Bisacodyl|
|Mode of Action||Retains water in the bowel to soften stools and increase the frequency of bowel movements.||Adds bulk and allows more water to remain in stools; making them larger, softer, and easier to pass.||Works by stimulating the muscles of the bowel to accelerate the stool’s journey through the colon.|
|Form||Generally available in powder form.||Generally available in powder and oral pill form.||Generally available in oral pill, liquid, or suppository form.|
|Example of Brands||RestoraLAX®, Phillips Milk of Magnesia|
|Examples of Medical Ingredients||Polyethylene glycol, Magnesium hydroxide|
|Mode of Action||Retains water in the bowel to soften stools and increase the frequency of bowel movements.|
|Form||Generally available in powder form.|
|Bulk-Forming (Fibre) Laxative*|
|Example of Brands||Metamucil®, Fibre ChoiceTM|
|Examples of Medical Ingredients||Psyllium, Inulin|
|Mode of Action||Adds bulk and allows more water to remain in stools; making them larger, softer, and easier to pass.|
|Form||Generally available in powder and oral pill form.|
|Example of Brands||Senokot®, Ex-lax®, Dulcolax®|
|Examples of Medical Ingredients||Sennosides, Bisacodyl|
|Mode of Action||Works by stimulating the muscles of the bowel to accelerate the stool’s journey through the colon.|
|Form||Generally available in oral pill, liquid, or suppository form.|
*for occasional constipation
†for constipation and/or regularity