Solve the constipation problem! A very detailed summary of drug treatment plans and precautions

Patients often ask doctors about their frequent constipation, difficulty in defecation, and hemorrhoids. They may even have difficulty in defecation for 2 to 3 days or longer, or have symptoms such as hard and dry stool, abdominal distension, bad breath, and loss of appetite, which makes them feel very painful. Is there a good way to relieve constipation? This article explains how to treat constipation and how to correctly choose treatment drugs.

What causes constipation?

1. Insufficient defecation power or delayed defecation time: The elderly, the weak, the bedridden, the postpartum, etc., will have insufficient defecation power due to the weakened contraction of the diaphragm, abdominal muscles, and anal sphincter, and the reduced abdominal pressure, which will lead to insufficient defecation power, so that the feces cannot be discharged cleanly, and feces remain, leading to constipation; young people often neglect to develop the habit of regular defecation or delay defecation time due to busy work, emotional tension, travel life, etc., so that the feces that have reached the rectum return to the colon; or for other reasons, such as anal diseases such as anal fissures and hemorrhoids, they dare not defecate due to fear of pain and bleeding, thus prolonging the interval between defecation. This may make the nerve cells on the rectal wall react slowly to the pressure generated by the feces entering the rectum, so that the feces stay in the rectum for a longer time without causing the feeling of defecation, thus forming habitual constipation.

2. Caused by drugs: such as iron supplements, antihistamines, M cholinergic receptor blockers; calcium carbonate, aluminum hydroxide preparations, sucralfate, potassium citrate bismuth, bismuth subcarbonate, gefurate, diphenoxylate, etc. in digestive system medications; antipsychotic drugs such as chlorpromazine, imipramine, amitriptyline, clozapine, doxepin, etc.; antidepressants, calcium channel antagonists, diuretics, etc. can all cause constipation.

3. Unhealthy lifestyle: Long-term sitting, lack of exercise, excessive stress in life, lack of sleep, etc. are also common causes of constipation.

4. Caused by certain diseases: Acute constipation is mostly caused by acute diseases such as intestinal obstruction, intestinal paralysis, acute peritonitis, cerebrovascular accident, acute myocardial infarction, allergic colitis, diverticulitis, perianal pain, etc. Therefore, the above diseases should be actively treated.

Long-term constipation is harmful

1. Causing hemorrhoids: Constipation requires holding force during defecation, which increases the pressure in the rectal neck and blocks venous return. The normal anal cushions become congested and hypertrophic and repeatedly shift distally. The fibrous septa gradually relax until they break, accompanied by venous congestion, dilation, and fusion, and even small arteriovenous fistulas, which eventually form hemorrhoids.

2. Aggravate cardiovascular and cerebrovascular diseases: Elderly patients with constipation and cardiovascular and cerebrovascular diseases will exert too much force during defecation, which will increase blood pressure and oxygen consumption of the body, and can easily induce cerebral hemorrhage, angina pectoris, myocardial infarction, and even endanger their lives.

3. Formation of abdominal hernia: When constipation occurs, the intra-abdominal pressure suddenly increases due to excessive force during defecation, and the abdominal organs such as the small intestine protrude to the body surface through the weak part of the abdominal wall, which may form an abdominal hernia.

In view of this, constipation needs to be treated with medication or other methods for auxiliary treatment.

Drug treatment for constipation and dyspnea

Laxatives are a type of medicine that can promote intestinal peristalsis, increase the moisture content of feces, soften feces or lubricate the intestines to make feces easier to excrete. Commonly used drugs include osmotic, irritant and lubricating laxatives.

1. Osmotic laxatives: Osmotic laxatives are also called bulk laxatives. They are absorbed very little by the intestines after oral administration. They can increase the volume of the intestinal cavity and promote intestinal propulsive peristalsis, producing a laxative effect.

(1) Magnesium sulfate and sodium sulfate: Both are saline laxatives. They are not easily absorbed in the intestine after oral administration, and can increase the osmotic pressure in the small intestine, thereby hindering the absorption of water in the intestine. After the intestinal cavity is enlarged, it stimulates the intestinal wall, produces peristalsis, and causes the contents of the small intestine to quickly enter the large intestine and defecate. This type of drug has a fast and strong laxative effect. It is best to take it on an empty stomach in the morning, while drinking a lot of warm water, so that the salt solution can be easily discharged from the stomach into the small intestine to facilitate defecation.

Oral administration of magnesium sulfate can also stimulate the duodenal and jejunal mucosa, secrete cholecystokinin, cause relaxation of the common bile duct sphincter, and promote gallbladder contraction and emptying. It can also be used clinically to treat cholecystitis and cholelithiasis. The catharsis effect is mainly used to discharge the contents of the jejunum before surgery or colonoscopy, such as duodenal drainage examination, to assist in the discharge of some intestinal parasites or intestinal toxins. Usually 10-15g is taken with 250ml of warm water, and severe diarrhea can occur 1-4 hours after administration. However, about 20% of magnesium ions can be absorbed by the intestines, so patients with poor renal function or central nervous system depression may experience toxic reactions to magnesium ions. Such patients should use sodium sulfate because the catharsis effect of sodium sulfate is milder than that of magnesium sulfate. Because magnesium ions have a central nervous system inhibitory effect, sodium sulfate should be used for catharsis when poisoning by central nervous system inhibitory drugs (such as phenobarbital), and magnesium sulfate should not be used.

Sodium sulfate is easily soluble in water but not absorbed by the intestinal wall. It can form hypertonic salt in the intestine, absorb a large amount of water, expand the intestinal volume, stimulate the intestinal wall and cause defecation. Dosage: 5-20 g of powder at a time, dissolved in 250 ml of water, taken on an empty stomach in the morning; 5 g of enteric-coated capsules at a time, 1-3 times a day. The drug can be stopped after defecation. If there is no defecation after 12 hours, the drug can be taken 1-2 times more. It is contraindicated for patients with edema, pregnant women and those with organic intestinal lesions; it should be used with caution in the elderly, menstruating women and patients with severe heart, brain, lung, kidney diseases and severe failure.

Oral overdose of these two drugs can cause vomiting, thirst, abdominal pain, diarrhea, interfere with the absorption function of the small intestine, and reflexively cause pelvic congestion and dehydration. Therefore, they should not be used by pregnant women, menstruating women, patients with acute abdomen, the weak and the elderly.

(2) Lactulose: a disaccharide consisting of galactose and fructose. It is not absorbed orally and is decomposed into lactic acid by bacteria in the colon, which stimulates local exudation in the colon, increases the volume of the colon cavity and intestinal peristalsis, and promotes defecation. Lactic acid can also inhibit the absorption of ammonia and has the effect of lowering blood ammonia. Patients with intestinal obstruction, lactose or galactose intolerance, lactic acidemia, uremia, and diabetic ketoacidosis should not use it.

(3) Glycerin and sorbitol: They have mild irritating and laxative effects. They can take effect quickly after rectal administration and are suitable for the elderly and infirm and children with constipation. They should not be used by patients with diabetes, active intracranial bleeding, headache, nausea, vomiting, complete anuria, severe dehydration, acute pulmonary edema or precursors of acute pulmonary edema, and severe heart failure.

(4) Cellulose: such as plant cellulose and methyl cellulose. They are not absorbed by the intestines after oral administration, but increase the volume of the intestinal cavity, maintain the moisture of the feces, and have a good laxative effect.

(5) Polyethylene glycol: It can be used to treat constipation, preoperative intestinal cleansing preparation, colonoscopy, barium enema and other intestinal cleansing preparations. Take 1 to 2 bags per day, dissolve the drug in water and take it. Usually, diarrhea will occur within 4 hours after taking the drug, quickly cleaning the intestines.

It is contraindicated in patients with severe inflammatory bowel disease (ulcerative colitis, Crohn's disease) or toxic megacolon, gastrointestinal perforation or risk of gastrointestinal perforation, intestinal obstruction or suspected intestinal obstruction or symptomatic stenosis, and symptoms of unexplained abdominal pain.

(5) Compound Sodium Hydrogen Phosphate Tablets: This is a bulk cathartic drug suitable for intestinal cleansing preparation before surgery or colonoscopy, barium enema, or other intestinal examinations in adult patients. Each dose of this drug can produce a 1-3 hour catharsis.

It is contraindicated for patients with congestive heart failure, ascites, unstable angina, gastric paralysis or intestinal obstruction, severe chronic constipation, intestinal perforation, acute colitis, megacolon or hypomotility syndrome, or a history of allergy to sodium phosphate or other phosphate-containing preparations.

2. Stimulant laxatives: Stimulant laxatives are also called contact laxatives. The drugs or their metabolites stimulate the propulsive peristalsis of the colon wall, producing a laxative effect.

(1) Bisacodyl: It belongs to the diphenylmethane class. Its basic effect is similar to that of phenolphthalein (phenolphthalein has been eliminated and should no longer be used). It is in the form of enteric-coated tablets and should not be chewed or taken. It also has anal suppositories. After rectal administration, it can be converted into active metabolites, which have a strong irritating effect in the colon. Generally, it takes effect within 6 hours after oral administration and 15 to 60 minutes after rectal administration, resulting in soft stools. It can be used clinically to treat acute constipation, chronic constipation, habitual constipation, or to clean the intestines before abdominal X-ray examination, endoscopy, and before and after surgery. The drug is highly irritating and can cause intestinal spasms, proctitis, etc. Therefore, continuous use should not exceed 10 days. It is contraindicated for patients with acute abdomen, inflammatory bowel disease, and severe electrolyte disorders. This product should be taken 1 hour after a meal, and antacids or milk should not be taken 2 hours before taking the drug.

(2) Anthraquinones: Rhubarb, senna and other drugs contain anthraquinones, which can be decomposed into anthraquinones in the intestines, stimulating colonic propulsive peristalsis, and causing soft stools or diarrhea in 4 to 8 hours. Danthraquinone is a free anthraquinone, and defecation can occur 6 to 12 hours after oral administration.

(3) Castor oil: a stimulant laxative. After oral administration, it is decomposed into ricinoleic acid in the duodenum, which stimulates the small intestine, increases peristalsis, and promotes excretion. Oral administration, 10-20 ml at a time, defecation can occur 2-8 hours after taking. It is forbidden to use with fat-soluble anthelmintics and is contraindicated for pregnant women. Common adverse reactions include nausea and vomiting.

3. Lubricating laxatives

(1) Liquid paraffin: It is a mineral oil. After oral administration, it is not digested and absorbed in the intestines, and it hinders water absorption. It can lubricate the intestinal wall and soften the stool. It is suitable for the elderly, children with constipation, and those with difficulty defecating after surgery. Long-term use will interfere with the absorption of fat-soluble vitamins and calcium and phosphorus, so it is not suitable for long-term use.

(2) Glycerin: Injecting 50% glycerin solution (enema) into the anus can stimulate the intestinal wall to cause a defecation reflex and also have a local lubricating effect, allowing defecation after a few minutes.

Laxatives should be used judiciously

Can laxatives be used for a long time? The answer is no! Except for cellulose, all other laxatives cannot be used for a long time. Long-term use of laxatives will cause many adverse reactions.

Senna leaves and rhubarb in stimulant laxatives contain anthraquinones. Long-term use can cause a large amount of pigment to deposit in the intestinal mucosa, turning the intestinal surface black, which is called melanosis coli. Under colonoscopy, light brown, tan or black pigmentation can be seen on the surface of the colon mucosa, presenting stripes, patches, and tiger skin-like changes. Long-term use of stimulant laxatives will produce drug dependence and cause changes in the intestinal microecology.

Therefore, different types of laxatives should be selected according to different situations. For example, to promote the excretion of toxins, salt laxatives such as magnesium sulfate and sodium sulfate should be selected; for general constipation, contact laxatives are often used; for the elderly, aneurysms, anal surgery, etc., lubricating laxatives are often used.

Many patients do not follow the doctor's advice and take various laxatives for a long time and continuously. This is not advisable. After the colon is completely emptied by a laxative, it takes 3 to 4 days to refill the colon. Therefore, continuous medication is inappropriate.

Other measures to promote bowel movements

Medication can only be used to relieve urgent needs. To truly solve the problem of constipation, changes must be made in lifestyle and eating habits. The causes of constipation are mostly due to dietary structure, lifestyle, drug factors, potential disease influence, etc. For example, patients with constipation should not consume too much fried, grilled, high-protein, and high-fat foods for a long time. They should eat more vegetables, fruits, oats, and drink more water. At the same time, establish good bowel habits. Colon activity is most active when waking up in the morning and after meals. It is recommended that patients with constipation try to defecate within two hours after waking up in the morning or after a meal, concentrate on defecation, and reduce interference from external factors.

Author: Zhang Xing, deputy chief pharmacist, and Cui Ting, deputy chief physician, Department of Gastroenterology, Zhongwei People's Hospital, Ningxia Hui Autonomous Region