Constipation means that the frequency of bowel movements is reduced. The number of stools in a week is less than 2 to 3 times, or 1 to 3 days before stool. The amount of feces is small and constipation is called when dry. However, a small number of people have always had a bowel movement once every 2 to 3 days, and the stool characteristics are normal. This situation should not be considered as constipation; for the same person, if the stool is changed once a day or once every 2 days, 2 Constipation should be considered when the bowel movement is performed once a day or longer.
Laxatives: Drugs that stimulate bowel movements or increase intestinal moisture, soften feces or lubricate the intestines to promote intestinal discharge.
Common drugs for constipation:
I. Volumetric laxative (loose medicine)
By retaining the moisture in the feces, increasing the water content of the feces and the volume of the feces, it acts as a laxative, mainly for patients with mild constipation, and should add enough liquid when taking the medicine. Commonly used drugs are psyllium, polycarbophil calcium, wheat bran, methyl cellulose and so on.
II. Osmotic laxatives
Osmotic laxatives can form hyperosmotic conditions in the intestines, absorb water, increase stool volume, stimulate intestinal peristalsis, and can be used in patients with mild to moderate constipation. Drugs include polyethylene glycol and unabsorbed sugars (such as lactulose). ) and salt laxatives (such as magnesium sulfate).
Polyethylene glycol 4000 is a purely physical drug. Due to its high molecular weight, it is not absorbed by the intestines, and does not decompose in the intestinal tract to produce organic acids, which can be used to treat constipation caused by various causes. Conforms to the physiological characteristics of the colon.
Lactulose is broken down into lactic acid and acetic acid by the bacteria in the intestines, increasing the acidity and osmotic pressure of the feces, increasing the stool capacity, stimulating intestinal peristalsis, producing a slow cathartic effect, and also having the effect of lowering blood ammonia. Promotes the growth of physiological bacteria. Lactulose is especially suitable for patients with habitual constipation, constipation and liver function decompensation, and can prevent and treat hepatic encephalopathy.
Magnesium sulfate is not easily absorbed by the intestine and is easily soluble in water. After oral administration, a hypertonic saline solution is formed in the intestine to prevent absorption of water by the intestinal tract, thereby increasing the internal volume of the intestinal tract, thereby stimulating the intestinal mucosa and causing the intestinal tract. Creeping is enhanced and defecation.
Magnesium sulfate may also promote the secretion of cholecystokinin-secretory hormone, and promote the secretion of pancreatic juice and intestinal juice through the latter, further increasing the intestinal content, while stimulating intestinal peristalsis and causing diarrhea.
Commonly used for bowel preparation before colon examination or catharsis after poisoning. This product is used with caution in patients with gastrointestinal bleeding and peptic ulcer, so as not to increase absorption and cause poisoning; constipation patients with renal dysfunction should also be used with caution.
III. Lubricating laxatives
It can lubricate the intestinal wall and soften the stool to produce a diarrhea. It has a mild diarrhea effect and is more suitable for elderly, children and patients with hypertension or aneurysms or acne and patients with difficulty in postoperative bowel movements. Including glycerin, honey, liquid paraffin, paraffin oil and docusate polyaldehyde.
The ratio of glycerin in each case is 52.8-58.3%. After rectal administration, it can produce osmotic effect and also produce lubricative diarrhea. Defecation is caused within a few minutes of medication.
IV. Irritant laxatives (contact laxatives)
There are mainly senna, phenolphthalein, castor oil and bisacodyl. These drugs can stimulate intestinal peristalsis and secretion, while increasing the exchange of water and electrolytes, causing loose stools. Excessive use of irritating laxatives can lead to malabsorption of fat and potassium, a common consequence of long-term use of these laxatives. Long-term use should be avoided as much as possible, and short-term and intermittent use is recommended.
After oral administration, phenolphthalein forms a soluble sodium salt in the intestine and alkaline intestinal fluid, which stimulates colonic peristalsis and inhibits intestinal absorption of water. Oral 6-8 hours to discharge soft stools, mild effect, once a medicinal effect for 2-4 days, suitable for chronic or habitual constipation. Because about 15% of it is absorbed after oral administration, it can be excreted with urine, and the alkaline urine is red.
V. Prokinetic agent
It is mainly a serotonin (5-HT4) receptor agonist. The benzamide 5-HT4 receptor agonist is itopride, mosapride and the like. By stimulating the 5-HT4 receptor of the gastrointestinal myenteric plexus, the release of acetylcholine is promoted, resulting in a full gastrointestinal motility from the esophagus to the anus. These drugs should be used with caution in patients with cardiovascular disease, especially in combination with drugs that affect cytochrome P450 such as erythromycin and fluconazole.
Highly selective 5-hydroxytryptamine 4 Receptor agonist Prucaropride shortens colonic transit time, is safe and well tolerated, and should be taken from small doses.
VI. Secretagogues stimulate intestinal secretion and promote bowel movements
Including rubiprostone and linaclotide, it can effectively treat constipation caused by morphine preparations.
VII. Microecological preparations
Commonly used drugs are compound Lactobacillus acidophilus and the like. Oral microecological preparations can supplement a large number of physiological bacteria, correct the flora changes during constipation, and promote the digestion, absorption and utilization of food.
There are many reasons for constipation, such as lack of crude fiber in food, substances that can stimulate bowel movements, poor bowel habits, weakened bowel movements, weakened bowel movements, and mechanical obstruction in the intestines. Therefore, in the treatment of constipation, in addition to first consider the correction of the patient’s eating habits and bowel habits, it should also be appropriate to use laxatives on the basis of treatment, in order to promote the discharge of feces and intestinal toxicants.
The principles of treatment for constipation are:
- Improve lifestyle, so that it conforms to gastrointestinal tract and defecation exercise physiology. Increase dietary fiber intake and water intake, and develop good bowel habits. Increase exercise;
- Adjust the psychological state, help to establish normal bowel reflex;
- Treatment of primary disease and accompanying disease, is conducive to the treatment of constipation;
- Avoid drug factors as much as possible, and reduce constipation that may be caused by drugs;
- For the rational use of drugs for the pathophysiology leading to constipation, should avoid the abuse of laxatives;
- Biofeedback treatment to correct improper and ineffective bowel movements.