第二十二章药理学是.ppt

;正常成人： 收缩压小于140 mmHg 舒张压小于90 mmHg 原发性高血压：占90%-95%发病机制不明 继发性高血压：是一些疾病的表现 ;根据药物在血压调节机制中的作用抗高血压药物分类 ; 三、1.血管紧张素I转换酶抑制剂 2.血管紧张素II受体阻断药 四、钙通道阻断药 五、血管扩张药 1. 直接扩张血管药 （肼屈嗪、硝普钠） 2. 钾通道开放药 （米诺地尔、吡那地尔）; Hypertension is a common disease of great importance. It affects about 15%-20% of the total population of Chinese adults. The control of blood pressure is complex and involves vascular, cardiac, and renal physiology. ;The aims of antihypertensive therapy are to relieve or forestall symptoms, to prevent complications, and to prolong life. Furthermore, therapy should be individualized rather than blindly following a sequential list of drugs. ; All antihypertensive drugs have adverse effects that are particularly important in treatment of hypertension since most hypertensive patients are free of symptoms for most of the time. Therefore, any adverse drug effect, no matter how trivial, will make the patient feel worse ;Five classes of antihypertensive drugs are currently used 1. diuretics decrease blood volume 2. Sympathetic nervous system depressants reduce sympathetic outflow resulting in a decrease in heart rate, cardiac output and renin release.;3. Drugs that interfere with the renin-angiotensin system block the synthesis of angiotensin leading to a decrease in levels of the circulating vasoconstrictor. 4. Calcium channel blocker inhibite the entrance of calcium in to cells, causing a decrease in afterload . 5. vasodilators dilate blood vessels and reduce cardiac preload.;一、主要影响血容量的药物——利尿药 常用的是噻嗪类，单用有抗高血压作用，可 使患者血压平均降低约10%左右。 利尿药的降压机制: 早期:排钠利尿，造成体内钠、水负平衡，血容量减少，心输出量减少，降低血压。 ;长期： 1）动脉平滑肌细胞内低钠，Na+-Ca2+交换，细胞 内钙含量减少 2）血容量轻度降低 3）血管平滑肌上的α受体、血管紧张素Ⅱ受体， 对NA、血管紧张素等的敏感性降低 4）诱导血管壁产生扩血管物质，如激肽、前列腺 素; 氢氯噻嗪 【药效学】 氢氯噻嗪 12.5-25.0 mg/天，可使多数病人 达到抗高血压的作用 加大剂量，心血管病的发生率和死亡率增加;【不良反应】 阳痿、痛风、 低钾 缺钾促发两种室性心律失常： 尖端扭转型心律失常