The Mechanism Of Action: How Do Depositories And Laxatives Work?

Laxatives are a type of medicine used to treat constipation. They work by softening stools or stimulating the bowels to make it easier to pass stool. Laxatives can be taken orally or via the rectal route of administration. They are available over the counter and on prescription. There are several types of laxatives, including bulk-forming laxatives, osmotic laxatives, stool softeners, lubricants, and stimulants. They work in different ways, but all aim to make it easier to pass stool. For example, bulk-forming laxatives increase the weight of the stool, which stimulates the bowel. Osmotic laxatives draw water from the body into the bowel to soften the stool. Lubricant laxatives coat the colon, making it slippery and preventing water absorption from the stool.

Bulk-forming laxatives stimulate bowel movement by drawing water into the stool

Bulk-forming laxatives are a type of laxative that treats constipation by increasing the "bulk" or weight of the stool. This increase in bulk stimulates the bowel to push out the stool. They are considered the gentlest type of laxative and are usually recommended as the first line of treatment for constipation. They are also generally safe for healthy individuals.

These laxatives work by drawing water from the body into the stool, making it softer, bulkier, and easier to pass. The soluble fibre in bulk-forming laxatives is the ingredient responsible for this water absorption. This increase in water content and bulk helps to move the stool more quickly through the colon. As a result, the colon contracts and is stimulated to push out the stool.

It is important to note that bulk-forming laxatives can take longer to work compared to other types, typically between 12 hours to 3 days. Additionally, they should be taken with plenty of water to prevent dehydration and potential side effects such as bloating and gas.

Some common bulk-forming laxatives include psyllium (Metamucil), polycarbophil (FiberCon), and methylcellulose (Citrucel). They are available over the counter in pharmacies, grocery stores, and online.

Osmotic laxatives soften stools by drawing water from the body into the bowel

Osmotic laxatives are a type of medication used to treat or prevent constipation. They work by drawing water from the body into the colon, thereby softening stools and making them easier to pass. This process typically takes 2-3 days, and osmotic laxatives are available over the counter or by prescription.

Osmotic laxatives are particularly useful for those with infrequent and hard-to-pass stools, which are usually hard and dry. By increasing the amount of fluid in the intestines, osmotic laxatives help to soften the stools. The term "osmotic" refers to the movement of fluid through a membrane so that the concentration is equal on both sides. In the case of osmotic laxatives, substances like salts, sugars, and other organic compounds encourage the movement of water into the lumen (the inside of the colon).

Osmotic laxatives differ from other types of laxatives, such as emollient and lubricant laxatives, in that they can be used to prevent or treat chronic constipation. Emollient laxatives, also known as stool softeners, work by increasing the water and fat that the stool absorbs, thereby softening it. Lubricant laxatives, on the other hand, coat the colon with an oily substance, making it easier for the stool to slip through the intestine.

Common osmotic laxatives include polyethylene glycol (PEG), lactulose, sorbitol, magnesium citrate, and magnesium hydroxide (Milk of Magnesia). These laxatives can be found in various forms, including oral solutions, powders, and tablets, and are typically well-tolerated, with mild side effects that resolve within a couple of days. However, overuse of osmotic laxatives can lead to dehydration and the loss of important electrolytes like sodium, calcium, and potassium. Therefore, it is important to follow the dosing instructions carefully and only use laxatives when needed.

Lubricant laxatives coat the colon with mineral oil, making stools slippery

Lubricant laxatives, such as mineral oil, are used to treat constipation. They work by coating the intestinal wall and stool with a waterproof film layer, which prevents the stool from drying out and makes it slippery. This coating also helps the intestines to retain moisture by reducing water absorption, ensuring the stool remains soft and easy to pass. Lubricant laxatives are best used as a short-term cure for constipation, as long-term use can lead to vitamin deficiencies and other issues.

Lubricant laxatives are typically taken orally, and it may take 6 to 8 hours for them to cause a bowel movement. It is important to carefully follow the dosage instructions provided by a doctor or the product package. Lubricant laxatives should not be taken by older adults, children under 6, or bedridden individuals without medical advice. They can cause side effects such as anal seepage, pruritus ani, perianal discomfort, and intestinal malabsorption.

Lubricant laxatives are particularly useful for treating fecal impaction, a large, hard mass of stools stuck in the colon or rectum. They can also be used as antacids in some cases. While effective, they are not the first choice for treating constipation. Bulk-forming laxatives, which are gentler and safer, are usually recommended first.

Stimulant laxatives stimulate the nerves controlling the muscles in the colon

Laxatives are medicines that treat constipation by softening hard stools or stimulating the bowels to get moving. Stimulant laxatives are one of the five basic types of laxatives, the others being osmotic, bulk-forming, stool softeners, and lubricants.

Stimulant laxatives are available in various forms, including liquids, powders, chewables, tablets, and suppositories, and can be purchased over the counter. However, they should not be used regularly or daily, as they may weaken the body's natural ability to defecate and cause laxative dependency. It is important to follow the directions on the label and consult a doctor before use, especially if you are pregnant or breastfeeding.

Prescription laxatives are required when over-the-counter options are ineffective

Laxatives are medicines that treat constipation by softening stools or stimulating the bowels to move. They are usually available over the counter and include bulk-forming laxatives, osmotics, stool softeners, lubricants, and stimulants. However, prescription laxatives are required when over-the-counter options are ineffective or when constipation is caused by a chronic condition.

Over-the-counter laxatives are meant for short-term relief from occasional constipation. They should not be used for more than a week without consulting a doctor. Prolonged use of these laxatives can worsen constipation and lead to serious medical issues, including addiction. On the other hand, prescription laxatives are deemed safer for long-term use and are often necessary for individuals with chronic constipation or constipation caused by conditions like irritable bowel syndrome (IBS) or opioid use.

Bulk-forming laxatives, also known as fibre supplements, are typically recommended as the first course of treatment. They work by drawing water into the stool, making it softer and easier to pass. Examples include psyllium (Metamucil®), polycarbophil (FiberCon®), and methylcellulose (Citrucel®). These laxatives are considered the gentlest and are less likely to cause side effects such as bloating and gas. However, they may take several days to provide relief.

If bulk-forming laxatives are ineffective, osmotic laxatives like polyethylene glycol (MiraLAX®) can be prescribed. These products hold water in the stool, softening it and increasing bowel movements. Common side effects include gas, bloating, and nausea. Lubricant laxatives, such as mineral oil, are another option, but they should not be used long-term as they can interfere with vitamin absorption.

Stimulant laxatives, which activate the nerves controlling the muscles in the colon, are a last resort. They include bisacodyl (Dulcolax®) and senna (Fletcher's® Laxative). These laxatives are effective in providing quick relief but carry a risk of dependency and side effects such as cramping and diarrhoea.

In summary, prescription laxatives are necessary when over-the-counter options fail to provide relief or when constipation is chronic or related to an underlying condition. It is essential to consult a healthcare provider to determine the best course of treatment and ensure safe and effective use of laxatives.

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