医学课件消化系统药物

消化系统药物,Digestive System Agents,Common gastrointestinal symptoms Dyspepsia胃炎 Peptic ulcer disease胃溃疡 Diarrhea泄泻 Constipation便秘,抗消化性溃疡药 消化性溃疡主要十二指肠溃疡、胃溃疡，其发病系保护与攻击因子失平衡有关。,抗消化性溃疡药 消化性溃疡主要指发生在胃和十二指肠的慢性溃疡，具有自然缓解和反复发作的特点。 临床主要症状：反酸、嗳气、周期性上腹部疼痛。 发病机制：损伤胃肠粘膜的攻击因子增强或防御因子减弱所致。,Types of Ulcers,胃壁细胞受体,胆碱受体（M）,胃泌素受体,组胺受体（H2）,激活受体，开放钙通道， 最后激活H+,K+-ATP酶， 分泌H+到胃内,胃酸分泌,前列腺素受体 前列腺素E，保护胃粘膜.,根据胃酸分泌机制：,H2-受体拮抗剂H2 blockers 质子泵抑制剂proton pump inhibitors 中和过量胃酸的抗酸药antacids,理想抗酸药应该是作用强、迅速、持久、不吸收、不产气、不引起腹泻或便秘，对粘膜及溃疡面有保护收敛作用。 本类药物作用基本相同，主要区别在于吸收程度、作用快慢、持续时间和不良反应。,抗酸药,抗酸药 弱碱性物质，中和胃酸，减轻对胃粘膜的刺激和腐蚀。 氢氧化镁：抗酸较强，较快，有轻度致泻作用（Magnesium Hydroxide）,氢氧化铝：抗酸较强，缓慢，可致便秘（Aluminium hydroxide） 影响四环素的吸收（形成络合物）。 碳酸氢钠：抗酸弱，快而短暂，可吸收，产生CO2。用于酸中毒；碱化血及尿液；很少用于抗胃酸Sodium bicarbonate,一般不单用,抗组胺药物,组胺的作用 在20世纪40年代，发现 涉及变态反应，损伤和胃分泌的生理调节 抗组胺药物有效地减弱组胺的许多反应 抗过敏疾病 (现在把这批抗组胺药叫作H1受体拮抗剂) 但不能拮抗胃部组胺对胃酸分泌的促进作用,H1受体和H2受体,存在组胺受体的两个亚型 H2受体 在胃壁细胞存在 与胃酸分泌有关,H2-receptor antagonists,Four FDA-approved: Cimetidine 西咪替丁 （Tagamet） Ranitidine 雷尼替丁 （Zantac） Famotidine 法莫替丁（Pepcid）,Therapeutic effects: Promote the healing of gastric and duodenal ulcers (胃和十二指肠溃疡) Gastroesophageal reflux dz GERD (反流性食道炎) Upper GI bleed GIB (上消化道出血) May be effective in stress ulcers (应激性溃疡) & peptic esophagitis (消化性食道炎),H2-receptor antagonists,H+,K+-ATPase (Proton Pump) inhibitor Omeprazole 奥美拉唑 (Prilosec) Lansoprazole 兰索拉唑 (Prevacid) Pantoprazole 泮托拉唑 并且作用最强、效力长久，选择性高，副作用小,质子泵抑制剂 Proton pump inhibitors,Therapeutic uses,Gastroesophageal reflux dz GERD (反流性食道炎),有效率达7585。 Peptic ulcer（消化性溃疡）,服用16月，溃疡愈合率达97，其它类药物无效用4周，愈合率达90。 Infection with H. pylori plus(Hp) (幽门螺杆菌感染),幽门螺旋杆菌83%88转阴。 Upper GI bleed GIB (上消化道出血),Agents Used in infection of Helicobacter Pylori,幽门螺杆菌（helicobacter pylori，HP ）为革兰阴性厌氧菌， 在胃十二指肠的粘液层与粘膜细胞之间生长，可产生多种酶及细胞毒素，使粘膜损伤。 是慢性胃炎、消化性溃疡和胃腺癌等胃部疾患发生发展中的一个重要致病因子。,FDA-Approved Treatment Regimens for H.pylori Infection,Omeprazole 20mg b.i.d + Clarithromycin 500mg b.i.d + Amoxicillin 1g b.i.d for 10 days Lansoprazole 30mg b.i.d + Clarithromycin 500mg b.i.d + Amoxicillin 1g b.i.d for 10 days Bismuth subsalicylate 525mg q.i.d + Metronidazole 250mg q.i.d + Tetracycline 500mg q.i.d 14 days + H2 receptor antagonist 4 wks,电镜下幽门螺杆菌,有何副作用？有何困难？,Lacteol forte 乳酸杆菌干燥物，抑制腐败细菌生长、繁殖及防止蛋白质发酵，减少肠内产气，促进消化和止泻作用。 临床应用：消化不良、腹胀,Digestives 助消化药,还有什么其他用途？,Clinical classification of diarrhea,见泻止泻？,Loperamide洛哌丁胺,Loperamide洛哌丁胺 可抑制肠道平滑肌的收缩，减少肠蠕动 各种原因引起的非感染性急、慢性腹泻的对症治疗 Slows intestinal motility, allowing absorption of electrolytes and water through the intestine Helps relieve cramps and decrease stool frequency For travelers diarrhea, nonspecific acute diarrhea, or chronic diarrhea associated with inflammatory bowel disease Side effects: dizziness, constipation,Loperamide洛哌丁胺,对于伴有肠道感染的腹泻，必须同时应用有效的抗生素治疗。 不应用于需要避免抑制肠蠕动的患者，尤其是肠梗阻、胃肠胀气或便秘的患者。 腹泻患者常发生水和电解质丧失，应适当补充水和电解质。 用药过程中出现便秘或 48小时仍无效者应停药。,Lomotil,Atropine sulfate 25mcg + diphenoxylate HCl 2.5mg 地芬诺酯+阿托品 Dose: 2 tab tds-qds (max: 8 tab/day),乙酰胆碱acetylcholine,Drug treatment for diarrhea,Kaolin Adsorbents For mild nonspecific acute diarrhea Adsorb 吸附everything in the GI tract Negligible systemic absorption Side effects: constipation, bloating, fullness Others : Charcoal, Smecta,思密达Smecta,蒙脱石散剂 该药不进入血液循环系统，并连同所固定的攻击因子随消化道自身蠕动排出体外 不改变正常的肠蠕动 成人及儿童急、慢性腹泻 如需服用其它药物，建议与该药间隔一段时间,便秘Constipation,Causes:因素 Disease tumors, hypothyroidism, diabetic neuropathy Drug narcotic analgesics, aluminium-containing antacids, amitriptyline Psychogenic depression, eating disorders (anorexia), conscious efforts to withhold stool Lifestyle low-fibre diet, inadequate intake of fluids, avoiding the urge to empty the bowel,Type of laxatives,Bulk-forming laxatives e.g Fybogel, fibrosine Emollient laxatives e.g Docusate sodium Lubricant laxatives e.g Mineral oil Saline laxatives e.g Fleet enema Hyper-osmotic laxatives e.g. Lactulose, Glycerin Stimulant laxatives e.g Senna, Bisacodyl,Bulk-forming laxatives,纤维 Considered safest among all laxatives Safe for long term use Works in 1 3 days Sufficient fluid consumption is required (usually a glass)喝足够水 Side effects : bloatedness, abdominal discomfort,Lubricant laxatives,油性Mineral oil coats and softens stool Recommended for patients who need to avoid straining (hemorrhoid surgery, childbirth). Normally short term use短暂用 Can cause pneumonia if it leaks into the lungs Not recommended for the elderly, stroke victims, and those with swallowing difficulties They are prone to aspirate, especially while lying down or at bedtime,Hyper-osmotic laxatives,Lactulose type is a special sugar-like laxative Induce bowel movements by drawing water into the bowel from surrounding body tissues This provides a soft stool mass and increased bowel action Often used for long-term,乳果糖 lactulose,乳果糖还具有双糖的渗透活性，可使水、电解质保留在肠腔而产生高渗效果，故又是一种渗透性泻药，因为无肠道刺激性，亦可用于治疗慢性功能性便秘。 糖尿病患者慎用，对半乳糖不能耐受者不宜服用？,Stimulant laxatives,Induce bowel movements by increasing the contraction of muscles in the intestines肠蠕动 Normally for short term use短暂用 Usually takes 8 to 20 hours to work Side effects include cramps, excess fluid loss Prone to abuse滥用 番泻叶senokot，比沙可啶bisacodyl,Prokinetic agent,Domperidone多潘立酮（又名吗丁啉） (dopamine antagonist) Promotes or increases co-ordination of contractions of the gastrointestinal tra