What is the function of laxatives?

Question 1: What laxatives are used to promote defecation, mainly for constipation or excretion of enterotoxin? According to its action nature, it can be divided into four categories: the first category, volumetric laxatives (also known as salt laxatives or mechanical laxatives). These drugs are not easy to be absorbed by the intestine after oral administration, but soluble in water, which increases the osmotic pressure in the intestine and absorbs a lot of water, so that the intestine cannot absorb water. Therefore, a large amount of water stays in the intestine, which increases the volume, expands the intestine, and produces * * * on the intestinal mucosa, which enhances the peristalsis of the small intestine through reflection and promotes the contents to quickly enter the large intestine to cause diarrhea, thus achieving the purpose of defecation. Commonly used are magnesium sulfate, sodium sulfate, methylcellulose, agar and so on. The second category, * * * laxatives. Such drugs themselves or their catabolic products can * * * intestinal wall, increase intestinal peristalsis and promote fecal excretion. Commonly used drugs are phenolphthalein, castor oil, rhubarb, senna and so on. The third category, lubricating laxatives. It is not absorbed in the intestine after oral administration, which hinders the absorption of water, so it has the functions of softening stool and lubricating intestinal wall, and is suitable for hemorrhoids, hypertension, constipation of the elderly and children after operation. The commonly used medicine is liquid paraffin. Usually the dosage is 5 ~ 15ml/ time, which can hinder the absorption of fat-soluble vitamins AD, K, calcium and phosphorus, so it is not suitable for long-term use. The fourth category is laxatives. These drugs are surfactants with soft stool function, which can reduce the surface tension of feces, make water soak in feces, swell and soften, and be easily discharged. Such as sodium octyl butyl sulfonate.

Question 2: What are the commonly used laxatives in clinic? They fall into the following categories:

The first category is volume laxatives, also known as plant laxatives, including methylcellulose, agar, pectin and so on. This laxative is not absorbed by the intestinal wall, but expands after absorbing water in the intestine, expanding the intestinal volume and causing defecation reflex; It can also be mixed with feces to soften feces. This kind of medicine has poor curative effect, but it is economical and practical, with few adverse reactions, and can be used by people with constipation. These drugs can not increase colon tension, so they are not suitable for patients with weak colon and poor intestinal peristalsis.

The second category is * * * laxatives, which are often used after the use of volumetric laxatives is ineffective. Representative drugs are Senna, rhubarb, phenolphthalein (fruit-guiding tablets), bisacodyl (laxative), castor oil and so on. These drugs themselves or their metabolites can * * * intestinal wall, increase intestinal peristalsis and promote defecation. It is characterized by fast catharsis and strong drug effect, and it is the first choice for those who need to defecate quickly. However, because most of them contain anthraquinones, long-term use will cause drug dependence, colon lesions and even induce intestinal polyps, so it is not advisable to use them for more than one week, and pregnant women and lactating women are prohibited. Among them, rhubarb, guide tablets and so on. It has a slow effect and should be used before going to bed. Huang Yi injures the spleen and stomach, and is not suitable for constipation patients caused by deficiency of qi and blood.

The third category is lubricating laxatives, and the representative drugs are kaisailu, liquid paraffin, and dongku ester sodium. This kind of medicine has the function of moistening intestines and softening stools, can help constipation patients to defecate easily and prevent overexertion, and is suitable for patients with hemorrhoids, anal fissure, postoperative, hypertension history and long-term bed rest. This kind of medicine takes effect quickly, but the action time is short, and it has a burning sensation after rectal use. Long-term use will affect the absorption of fat-soluble vitamins and calcium and phosphorus, so it is not suitable for long-term use. Moreover, after the rectum is frequently opened, the sensitivity will be reduced and defecation will be more difficult.

The last category is osmotic laxatives, and the representative drugs are magnesium sulfate (salt laxatives), lactulose, mannitol, sorbitol and polyethylene glycol (Fusong). These drugs are absorbed slowly in the intestine, so they can maintain the high osmotic pressure in the intestine and prevent the salt and water in the intestine from being absorbed, thus expanding the intestine and promoting peristalsis. Large-dose and long-term use of this kind of drugs can cause water-electrolyte disorder, diarrhea and constipation alternately, so it is appropriate to use small doses. Among them, magnesium sulfate is generally used to repel insects and eliminate intestinal toxins. Diabetic patients should use lactulose with caution to avoid affecting blood sugar level.

Other common laxatives are intestinal motility drugs (Kailening, etc. ) and 5D serotonin receptor agonist (tegasero et al. ), can strengthen intestinal muscle tension, accelerate intestinal movement and promote defecation, but often lead to mild abdominal pain, diarrhea and other symptoms.

Question 3: What are the precautions when using laxatives? The principle of using laxatives is to temporarily relieve symptoms and should usually be avoided as much as possible. Bulk molding is the only laxative that can be used for a long time. Include plantain, polycarbophil and methylcellulose, for mild constipation, preferably for those with normal transmission test. After taking 12 to 24 hours, it takes effect slowly and reaches the best effect after a few days. You must drink a lot of water to use this medicine. It is easy to appear when the dose increases too fast, and usually disappears after a few weeks. Obstructive diseases of digestive tract can be banned. Including lactulose (Dumex), PEG4000 (Fusong) and so on. It takes effect quickly and is suitable for the decomposition of lactulose to produce lactulose during acute constipation. It can be used for defecation effortlessly, such as patients after myocardial infarction, stroke and abdominal surgery. Long-term use affects the absorption of fat-soluble vitamins A, D, E and K, and long-term use leads to osteomalacia. Long-term use will affect immune function, and it is best not to use it for more than two weeks. Phenolphthalein (fruit guide), glycerin suppository, kaisai dew, senna leaf, rhubarb and aloe are usually used for acute constipation, and are not recommended for children and adolescents. Often misused, it will lead to intestinal nerve injury and transit constipation. Normal saline takes effect quickly and is suitable for acute constipation. You should take it on an empty stomach in the morning and drink plenty of water. When defecation reflex is weakened, this product should be banned for catharsis. Intestinal bleeding, pregnant women, patients with acute abdomen and menstrual women are forbidden to use this product for catharsis. Taking too high a concentration of solution will lead to dehydration of tissues. When central depressant poisoning requires catharsis, magnesium sulfate should be avoided and sodium sulfate can be used.

Question 4: What kinds of laxatives can be divided into and what is the clinical value? Laxatives can increase the moisture content in feces and accelerate the operation of intestinal contents. According to the mode of action of laxatives, laxatives can be divided into four types: volume, permeability, contact and lubricity. (1) Volumetric laxative: dietary fibres is an undigested carbohydrate such as cellulose, hemicellulose and pectin in plant food, which belongs to volumetric laxative. Semi-synthetic polysaccharides and cellulose derivatives, such as methylcellulose, also belong to volumetric laxatives. Undigested food cellulose, semi-synthetic polysaccharides and cellulose derivatives that cannot be digested by human beings are hydrophilic. After absorbing water and swelling in the intestine, the volume of intestinal contents increases, intestinal peristalsis is promoted, and soft stools are discharged. (2) osmotic laxatives: osmotic laxatives include salts (such as various magnesium salts, sulfates and phosphates), disaccharides (such as lactulose), glycerol and sorbitol. It is difficult or slow for drugs to be absorbed in the intestine, so high osmotic pressure is maintained in the intestinal cavity to prevent the intestinal tract from absorbing salt and water, which leads to the increase of intestinal volume, the expansion of intestinal cavity and intestinal wall and the promotion of intestinal peristalsis. In addition, magnesium salt can also secrete cholecystokinin from duodenum, promoting intestinal secretion and peristalsis. (3) Contact laxatives: once called * * * laxatives. After these drugs come into direct contact with mucosa, the permeability of mucosa increases, and electrolyte and water penetrate into intestinal cavity, thus increasing intestinal fluid and causing defecation. Because these drugs have both exciting and inhibitory effects on intestinal activities, and they also have major effects on intestinal mucosa to absorb water and electrolytes, they are renamed as contact laxatives. These drugs include anthraquinones (such as rhubarb, senna, aloe) and diphenylmethane (such as phenolphthalein), which have little effect on the function of small intestine, and mainly act on large intestine, which can not only reduce its segmental movement, but also increase its periodic peristalsis, thus accelerating the operation of large intestine contents. In addition, these drugs can also reduce the absorption of water and electrolytes by intestinal mucosa. (4) Lubricating laxatives: also known as stool softener, which mainly plays a lubricating role and is beneficial to defecation. Such as liquid paraffin, honey, etc. In addition, glycerol also has local lubrication effect. The clinical application value of laxatives mainly includes the following aspects: (1) Treating constipation: For habitual constipation, we should start with adjusting diet, eat more foods rich in dietary fiber, such as vegetables and coarse flour, and develop good defecation habits. When laxatives must be used, they should be selected reasonably according to the characteristics of each drug. Occasional acute constipation can be injected with 50% glycerol or kaisailu * * *, 20ml for adults and 0/0 ml for children or reduced as appropriate. (2) Eliminating intestinal toxicants: For food poisoning or drug poisoning, oral salt laxatives, such as sodium sulfate or magnesium sulfate, should be taken quickly and strongly, which can block or delay the progressive absorption of toxicants caused by the increase of intestinal osmotic pressure. (3) Auxiliary deworming: If you have poor defecation after taking anti-worm drugs, you can take magnesium sulfate to promote worm excretion. It must be noted that laxatives should not be abused when the diagnosis of abdominal pain is unclear.

Question 5: What else has the same effect as laxatives? No food has the same laxative effect. But the foods that moisten intestines are bananas, honey and sesame (oil).

Question 6: What are the benefits of taking laxatives? Eating a small amount of laxatives can relieve bloating, but eating a lot for a long time will cause constipation.

Question 7: What is the most effective laxative? First aid guide film. Guide film.