中医中药药理学外文版 (41).pdf

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1、Chapter 22 Drugs for Digestive Disorders【Learning points】Digestive system drugs include anti-peptic ulcer drugs,digestive aids,antiemetic drugs,laxatives,antidiarrheal drugs,and choleretic drugs.Section 1 Anti-peptic ulcer medicine 1.Neutralizing stomach acid medicine It can neutralize gastric acid,

2、and then reduce the acidity of gastric contents,relieve gastric acid on erosion of stomach and duodenal mucosa and the stimulation of the ulcer,and reduce pepsin activity.Commonly used drugs are magnesium hydroxide,magnesium trisilicate,aluminum hydroxide,calcium carbonate,sodium bicarbonate and so

3、on.2.Drugs for inhibiting gastric acid secretion(1)Anticholinergic drugs：Atropine and its derivatives can reduce the secretion of gastric acid,and relieve gastrointestinal cramps.Therapeutic effect of pirenzepine is similar to cimetidine,and minor adverse reactions.(2)H2 receptor blockers:Cimetidine

4、,ranitidine,famotidine,etc.(3)H+-K+-ATPase inhibitors reduce gastric acid secretion by inhibiting H+-K+-ATPase.Commonly used drugs are omeprazole,lansoprazole,pandolazole,rabeprazole,etc.Its curative effect is better than H2 receptor blocker,and it is used for reflux esophagitis,peptic ulcer,upper g

5、astrointestinal bleeding,and helicobacter pylori infection.Adverse reactions are peripheral neuritis,increased the levels of serum transaminases and bilirubin.(4)Gastrin receptor blocking drugs:proglumide reduce gastric acid secretion by blocking gastrin receptors.Meantime,proglumide also block chol

6、ecystokinin receptors.Therefore,it is used to promote gastric emptying and treat pancreatitis.3.Mucosal protective drugs(1)Prostaglandin derivatives:Misoprostol can inhibit the secretion of gastric acid caused by basic gastric acid,histamine,gastrin and food stimulation,and also reduce pepsin secret

7、ion.It has effects on peptic ulcers and gastric bleeding caused by non-steroidal anti-inflammatory drugs,such as aspirin.Enprost acts like misoprostol,but it takes a longer time.(2)Sucralfate:It resists the erosion of gastric acid and digestive enzymes after adheres to the ulcer surface;it can promo

8、te the secretion of gastric mucus and bicarbonate;increase the role of growth factors to promote ulcer healing;inhibit Helicobacter pylori.It is effective in treating peptic ulcer,chronic erosive gastritis and reflux esophagitis.(3)Colloidal bismuth subcitrate:under the pH condition of gastric juice

9、,it can form bismuth oxide colloid and deposit on the surface of ulcer to form a protective barrier;combine with pepsin to reduce its activity;promote mucus and bicarbonate secretion;inhibit Helicobacter pylori.4.Anti-Helicobacter pylori medicine antibacterial drugs are the commonly used in the trea

10、tment of anti-Helicobacter pylori drugs,such as amoxicillin,tetracycline,gentamicin,and metronidazole.Anti-ulcer drugs,such as bismuth potassium citrate,H+pump inhibitor,sucralfate,etc.Section 2 Digestive function regulator 1.Digestive aids:The role and use of dilute hydrochloric acid,pepsin,pancrea

11、tin,and lactase.2.Antiemetic medicine (1)H1 receptor blocking drugs:Diphenhydramine and diphenhydramine are used to prevent motion sickness and inner ear vertigo.(2)M receptor blocker:Scopolamine is used to prevent motion sickness.(3)Dopamine receptor blocking drugs:Metoclopramide exerts antiemetic

12、effects by blocking CTZs dopamine D2 receptors;its also blocks 5-HT3 receptors in high doses;Metoclopramide blocks gastrointestinal dopamine receptors,and then increase gastrointestinal exercise to promote positive emptying of the stomach.Metoclopramide can cause extrapyramidal reactions in large do

13、ses of intravenous injection or long-term application.Domperidone blocks dopamine receptors and promotes gastric emptying,and then stops vomiting.Cisapride can promote the movement of esophagus,stomach,small intestine and colon.(4)5-HT3 receptor blocking drugs:Ondansetron can selectively block the 5

14、-HT3 receptors in the central and vagal afferent fibers,and then producing a strong antiemetic effect.Its Used for nausea and vomiting caused by tumor chemotherapy and radiotherapy.Section 3 Antidiarrheal drugs and adsorption drugs 1.Opiate preparation:Opiate tincture and compound camphor tincture u

15、sed for severe non-bacterial infectious diarrhea.2.Diphenoxylate:A pethidine derivative used for acute functional diarrhea.3.Loperamide:Haloperidol derivative used for acute and chronic diarrhea.Its antidiarrheal effect is fast,strong and lasting.4.Astringent:Tannic acid is released in the intestine

16、 to form a precipitate with the protein on the surface of the intestinal mucosa,attaches to the intestinal mucosa,reduces irritation,reduces inflammatory exudate,and plays a convergent and antidiarrheal effect.Used for various diarrhea.(5)Adsorption medicine:Activated carbon and white clay adsorb ga

17、s and poison in intestinal tract.Section 4 Laxatives 1.Irritant laxative(1)Phenolphthalein:After oral administration,phenolphthalein forms soluble sodium salts with alkaline intestinal fluid,stimulating colonic peristalsis.Phenolphthalein can make alkaline urine red.(2)Bisacodyl:Bisacodyl prevents t

18、he absorption of water and electrolytes,increases the intestinal volume and stimulates the colon.Mainly used for constipation,abdominal X-ray or endoscopy,and emptying of jejunum contents before surgery.(3)Anthraquinone rhubarb,senna,and aloe stimulate the colonic peristalsis.2.Osmotic laxative (1)M

19、agnesium sulfate and sodium sulfate:It is difficult to absorb in the intestine.A large dose of oral administration forms a high osmotic pressure to prevent the absorption of water in the intestine,expand the intestine,and promote intestinal motility.Mainly used for emptying intestinal contents befor

20、e surgery or colonoscopy;removing intestinal poisons and expelling some parasites.Oral high-concentration magnesium sulfate also has a biliary effect and can be used for obstructive jaundice and chronic cholecystitis.(2)Lactulose:can be used for chronic portal hypertension and hepatic encephalopathy.(3)Food cellulose,such as methyl cellulose and carboxymethyl cellulose,can prevent functional constipation.3.Slippery laxative Liquid paraffin,glycerin and cellulose smooth the intestinal wall and soften feces,making feces easy to expel,its suitable for children and the elderly.