LAXATIVES – INTRODUCTION
Laxatives are a type of medicine that can help you empty your bowels if you are having trouble going to the toilet.
Laxatives are milder in action and deal with evacuation of rectum. With use of laxatives, there is elimination of formed stools.
They are widely used to treat constipation if lifestyle changes haven’t helped. They are available over-the-counter, without a prescription, from pharmacies and supermarkets.
LAXATIVES – INDICATION
- Acute and chronic constipation
- Bowel preparation
- Chronic immobility
LAXATIVES – INFORMATION
Laxatives are probably more important to modern medicine for the harm they do than for their benefit. Use of the stimulant cathartics can lead to an atonic colon in which the neuromuscular apparatus is permanently damaged. Vigorous purgation may produce a paradoxical diarrhoea complicated by electrolyte derangement, malabsorption, and protein-losing enteropathy. Other than bran, most clinicians will have little need for laxatives and their use by patients should also be discouraged.
Types of laxatives
Foods (Mainly Plant-Based Foods)
The following foods may act as laxatives. They are more effective at preventing constipation than treating it:
Almonds, Aloe Vera, Apples/Apple Juice, Artichokes, Bananas, Basil, Beets, Blueberry, Carob, Chicory, Chios Mastic(gum), Cranberry, Coconut, Coffee, Cornmeal, Dandelion, Dates, Dried apricots, Endive, Fenugreek, Figs, Flaxseed, Grapes, Kale, Liquorice, Mangos, Molasses, Oranges, Papayas, Parsley, Peaches/Apricots, Pears, Persimmons, Pineapple, Plums, Prunes/Prune Juice, Rhubarb, Rutabagas, Soybeans, Strawberry, Tamarind, Tangerine, Tea, Tomato, Tomato Juice, Vanilla, Walnuts, Watercress, Winter Squash, Yams, Olive oil.
These work on the small and large intestine and generally take from 12 to 72 hours to work. They are also known as bulk-forming agents, bulking agents, and roughage. They make the stool become bulkier and retain more water.
Examples are: Metamucil (psyllium husk), Citrucel (methylcellulose), dietary fiber, broccoli, apples, and polycarbophil.
These work in the small and large intestine and generally take from 12 to 72 hours to work. They cause fats and water to penetrate the stool, making it easier to move down the digestive system. After prolonged use they become much less effective. They are effective for people with occasional constipation.
Examples are: Colace, Diocto (docusate)
These work in the colon and take from 6 to 8 hours to work. They make the stool slippery so that it moves down the intestine more easily and faster.
Example: mineral oil
Hydrating Agents (Osmotics)
These make the intestines hydrate (concentrate more water within), thus softening the stool. There are two types:
- Saline laxatives
These work on the small and large intestine and take from 30 minutes to 6 hours to work. They attract and retain water in the hollow of the intestine, the tube of the intestine (intestinal lumen), thus softening the stool. They also increase intraluminal pressure.
Examples: Dibasic sodium phosphate, milk of magnesia (magnesium hydroxide), Epsom salt (magnesium sulfate), monobasic sodium phosphate, sodium biphosphate, magnesium citrate.
- Hyperosmotic agents
These work in the colon and take from 30 minutes to 3 hours to work. Glycerin suppositories and Lactulose are examples. The glycerin suppositories work mostly by encouraging bowel movements by drawing water into the bowel from surrounding body tissues (hyperosmotic action).
Examples: Glycerin suppositories, Sobrbitol, Lactulose, PEG (polyethylene glycol)
These work in the colon. These work by stimulating the wave of contractions that pass along the colon propelling the stools along. Under certain circumstances they can be dangerous. Castor oil is sometimes more effective in achieving complete evacuation.
Example: Cascara, pholphthalein, Dulcolax (bisacodyl), Senna, Aloin (from Aloe Vera), castor oil, bisacodyl suppository, Microlax.
This works in the small intestine. It works directly on the mucosa in the intestines and alters water and electrolyte secretion.
Relistor (methylnaltrexone bromide)
Relistor is commonly used to treat patients with opioid-induced constipation (OIC). It is especially useful for patients with advanced illness who are receiving palliative care, when response to laxative therapy has not been sufficient.