Laxatives: Stimulant Or Not?

Laxatives are a type of medicine used to treat constipation. They work by softening hard stools or stimulating the bowels to get moving. There are four main types of laxatives: bulk-forming, osmotic, stool softeners, and lubricants. Bulk-forming laxatives increase the weight of the stool, stimulating the bowel to contract and push out the stool. Osmotic laxatives draw water from the body into the bowel to soften the stool and make it easier to pass. Stool softeners let water into the stool to soften it, and lubricants coat the colon to make the passage of the stool slippery. Stimulant laxatives are a type of laxative that triggers the intestines to contract and push out the stool. They are available over the counter and are typically recommended for short-term use only.

Bulk-forming laxatives

Some common bulk-forming laxatives include:

• Psyllium (Metamucil)
• Polycarbophil (FiberCon)
• Methylcellulose (Citrucel)
• Fybogel (ispaghula husk)
• During pregnancy or after giving birth
• Preparing for surgery
• Treating constipation in bedridden individuals
• Treating constipation caused by medication
• Preventing strain after surgery
• Restoring normal bowel function after a period of poor diet or physical inactivity
• Helping to reduce cholesterol
• Treating diarrhea

Additionally, bulk-forming laxatives may improve medical conditions exacerbated by straining.

Osmotic laxatives

How Osmotic Laxatives Work

Constipation occurs when stools are hard and difficult to pass. Osmotic laxatives increase the amount of fluid in the intestines, softening the stools. The term "osmotic" refers to the movement of fluid through a membrane to equalise the concentration on both sides. In the case of constipation, osmotic laxatives alter the balance by introducing substances like salts, sugars, and organic compounds that encourage water movement into the lumen (the inside of the colon).

How Osmotic Laxatives Differ from Other Laxatives

Common Osmotic Laxatives

• Polyethylene glycol (PEG): An organic compound derived from petroleum. Available over the counter as Miralax and GlycoLax.
• Lactulose: A type of sugar that is not absorbed by the intestine but instead ferments and produces fatty acids that draw water into the lumen. Available by prescription as Cephulac, Duphalac, and Kristalose.
• Sorbitol: Another non-absorbable sugar similar to lactulose. Available over the counter and by prescription as Arlex and GeriCare.
• Magnesium citrate: Magnesium in salt form combined with citric acid. OTC versions include Citrate of Magnesia, Citroma, and LiquiPrep.
• Magnesium hydroxide: A milder form of magnesium sold as Milk of Magnesia, also used as an antacid.

Possible Side Effects

Stool softeners

Natural stool softeners can also be achieved through lifestyle changes such as drinking more water, getting regular exercise, and increasing daily fibre intake.

It is important to note that stool softeners do not cause a bowel movement but rather allow you to go without straining. If you are experiencing constipation, it is recommended to try lifestyle changes first before opting for laxatives. If constipation persists or is chronic, consult a doctor for evaluation and guidance.

Lubricant laxatives

It is important to follow the instructions on the medication package to prevent side effects. Lubricant laxatives should be taken on an empty stomach as they can interfere with the absorption of certain vitamins. They should not be taken for more than 7 days unless directed by a doctor. It is also important to note that mineral oil may leak from the rectum, especially when taken at high doses, and can cause irritation or itching around the anus.

Stimulant laxatives

It is important to follow the directions on the label when taking stimulant laxatives and not to use them for more than a week unless advised by a doctor. Overuse of stimulant laxatives can lead to dependency, muscle loss in the colon, and other side effects such as discoloured urine. They should not be given to children under six without a paediatrician's recommendation.

Before taking stimulant laxatives, it is recommended to try lifestyle changes such as increasing fibre intake, drinking more fluids, and exercising regularly to relieve constipation.

Frequently asked questions