digestives 助消化药antiemetic drugs vomiting reflex.ppt

Drugs Affecting the Gastrointestinal System By Caiying Ye Department of Pharmacology, School of Basic Medicine, Peking Union Medical College Drugs Affecting the Gastrointestinal System 分类 Antiulcerants 消化性溃疡药 Digestives 助消化药 Antiemetics 止吐药 Purgatives 泻药 Antidiarrheals 止泻药 Cholagogues 利胆药 Peptic Ulcers 常见病，发病率约10%~12%. Pathogenesis of ulcers Aggressive Factors Defensive Factors Peptic Ulcers 溃疡 胃酸分泌过多 胃、十二指肠粘膜侵蚀，胃蛋白酶和幽门螺旋杆菌升高 消化性溃疡 治疗目的： Therapy is directed at enhancing host defense or eliminating aggressive factors; i.e., H. pylori. Drugs Used in Peptic Ulcers Antacids Inhibitors of gastric acid production H2-receptor antagonists Proton pump inhibitors Muscarinic antagonists Gastrin receptor antagonist Mucosal Protectants Anti-Helicobacter pylori. drugs Drugs Used in Peptic Ulcers 代表药物 Proton pump inhibitors 胃壁细胞H+泵抑制剂：omeprazole （奥美拉唑） Gastrin receptor antagonist 胃泌素阻断药：proglumide （丙谷胺） Mucosal Protectants 胃粘膜保护药：Prostaglandin Analog(前列腺素衍生物 ) misoprostol（米索前列醇） Anti-Helicobacter pylori. Drugs 抗幽门螺杆菌药：antibiotics 抗酸药 Antacids 抗酸药 Antacids 氢氧化镁magnesium hydroxide ① 抗酸作用强，较快，镁离子有导泻作用，与氢氧化铝合用，相互纠正副作用。 ② 小分子Mg2+可被吸收 肾排泄肾功能不良的病人 血清中Mg2+上升。 三硅酸镁magnesium trisilicate： 起效缓慢，作用持久，在胃内生成胶状二氧化硅，对溃疡具有保护作用。 抗酸药 Antacids 氢氧化铝aluminum hydroxide: 抗酸作用强，缓慢，持久，中和胃酸，具有收敛、止血和引起便秘作用。长时间应用影响磷酸吸收。禁止与四环素、地高辛、异烟肼、强的松等合用。 碳酸钙calcium carbonate： 抗酸作用强，快而持久，产生CO2气体，进入小肠，促进胃泌素分泌，反跳性胃酸分泌增加。 碳酸氢钠sodium bicarbonate（小苏打）： 作用强，快而短暂，产生CO2 ，碱血症。 H2-receptor antagonists Mechanism of action Competitively block the histamine (H2) receptor of acid-producing parietal cells rendering cells less responsive to not only histamine but also to the stimulation of acetylcholine and gastrin. Also up to 90% inhibition of vagal stimulated and gastrin stimulated acid secretion. complete inhibition has not been shown H2-receptor antagonists Four FDA-approved: Cimetidine 西咪替丁 （Tagamet?） Rani