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Chapter 3

Chapter 3. Pharmacodynamics. Contents. Contents. 1 、 Basic action 2 、 Therapeutic effect 3 、 Adverse reaction 4 、 Dose- effect relationship 5 、 Mechanism of action. 1 、 Basic action and Pharmacological effect. Drug action. Primary action. acting. drug. body. effect.

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Chapter 3

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  1. Chapter 3 Pharmacodynamics

  2. Contents Contents 1、Basic action 2、Therapeutic effect 3、Adverse reaction 4、Dose- effect relationship 5、Mechanism of action

  3. 1、Basic action and Pharmacological effect

  4. Drug action Primary action acting drug body effect second action

  5. Excitation: (兴奋) Two effect Inhibition: (抑制)

  6. 死亡 惊厥 Excitation 烦躁不安 强壮 正 常 正常 回苏 镇静 催眠 麻醉 Inhibition 麻痹 死亡

  7. drug two characteristics : 1) specificity (特异性) 2) Selectivity(选择性) (tissue binding)

  8. 2. Therapeutic effect 治疗目标 the therapeutic goal. Favorable to the normalization of physiological, biochemical functions.

  9. therapeutic effects 治疗效果 1、Etiological treatment 2、Symptomatic treatment 急則治标,缓则治本 标本兼治,不可偏废也

  10. 对因治疗 1) Etiological treatment Aims to eliminate pathogenic factor e.g. antibiotics----- microbes infection 2) Symptomatic treatment Aims to allay or ameliorate symptom e.g. analgesics --- analgesia 对症治疗

  11. Drug is a double edged sword !

  12. Accompanied by the therapeutic effect. • Appears at the therapeutic dose • Depends drug`s intrinsic action. • Expectable. • Can be moderated 3. Adverse reaction • Side reaction(副作用)

  13. Toxic reaction(毒性反应) • Results from overdose and excessive accumulation of drug • Can be expectable • Should be prevented

  14. 1)circulation Acute Toxic reaction 2)respiratory 3)nervous

  15. chronic Toxic reaction 1)liver,kidney 2)bone marrow 3)endocrine 4)other

  16.  ⑴ Carcinogenesis (致癌) chronic 4)other ⑵ Teratogenesis (致畸) ⑶ Mutagenesis (致突变)

  17. Residual effect (后遗效应 ) 血药浓度降至有效浓度以下时残存的效应。 • Withdrawal reaction (停药反应) rebound reaction(回跃反应): 突然停药后原有疾病加剧。

  18. Allergic reaction (变态反应) hypersensitive reaction (过敏反应) 1)unconcerned with dose (与剂量无关) 2)vary from drug to drug and person to person (因药而异,因人而异)

  19. Idiosyncrasy (特异质反应) 先天遗传异常 某些药物高敏。 genetic enzyme defects (遗传的缺陷), glucose-6-phosphate dehydrogenase (葡萄糖-6-磷酸脱氢酶)

  20. Concentration-effect relationship (浓效关系) Dose-response curve (量效曲线) Graded dose-response curve (量反应曲线 ) 量效关系 Dose-effect relationship (量效关系)

  21. 1. dose / dosage(剂量) 用药的分量 2、Dose-effect relationship 在一定的范围内药理效应 与剂量成正比。 3、dose-effect curve,D-E曲线 (量-效曲线)。

  22. 长尾S型曲线 对称S型曲线 E Emax 100% Emax 50% Log C (A) C (B) Fig 3-1 药物作用的量效关系曲线

  23. pD2 E 与亲和力成正比 100% 亲和力指数 50% pD2 0 0.1 1 10 30 C

  24. 量效曲线 作用强度 剂量 最小中毒量 最小有效量 常用量(治疗量) 最小致死量 极量

  25. Emax 100% Response (%) 50% EC50 ECmax Emin Emin 10 9 8 7 ECmin concentration

  26. Efficacy(效能) maximal effect(最大效应). Potency(效价强度): Relative concentration or dose of drugs inducing equivalent effects (等效浓度或剂量,EC50)

  27. 呋噻米 氢氯噻嗪 氯噻嗪 环戊噻嗪 各种利尿药的效价强度和最大效应比较

  28. 质反应的量-效曲线

  29. 质反应的量-效曲线 Quantal Dose-effect curves

  30. 药物效应和毒性的量效曲线

  31. therapeutic index 治疗指数 LD50 3 = TI TI ED50

  32. Drug A TI 药物安全性评价 Drug B E L 100% A B ………………….. 50% …...... ……. ED50 LD50 半数有效量(median effective dose , ED50 )

  33. TI 评价药物安全性不完全可靠 结论 可靠安全系数 (certain safety factor,CSF) CSF = LD1 / ED99>1 安全范围 ED95~ LD5之间的距离

  34. 量效曲线的意义 significance of dose-effect curve 1、评价药效: 1)半数有效量(ED50) 2)效能(efficacy) 3)效价强度(potency)

  35. 评价药物的安全性 2、评价药物的安全性 1)半数致死量(LD50) 2)治疗指数 (therapeutic index, TI) 3)可靠安全系数  (certain safety factor,CSF)

  36. §3 Drug 药物与受体 receptor

  37. receptor? to sense、recognize、bind some minimal chemical material and Trigger physiologior pharmacological effect a functional protein

  38. receptor drug

  39. Ligands 配体 endogenous ligands (内源性配体) 1)neurotransmitters神经递质 2)hormones激素 3)autocoid自体活性物质 exogenous ligands (外源性配体):drug

  40. 1)transmitter: Ach, NA, 3) autacoid: prostaglandin (前列腺素)histamine(组织胺) Endogenous ligands (乙酰胆碱,去甲肾上腺素) 2)hormone: adrenocorticoid, (肾上腺皮质激素) insulin(胰岛素), thyroxin (甲状腺素)

  41. receptor characteristics sensitivity (灵敏性): 剂量小 specificity (特异性): 结构要求高 saturability (饱和性): 数目有限 reversibility (可逆性):结合后可解离 multiple-variation (多样性): 分布不同,效应不同

  42. Drug-receptor interactions 相互作用 (-) (+) D+R DR - -E Two important factors 1)affinity(亲和力); 2)intrinsic activity,(内在活性α)

  43. affinity 能力 of D+R ? intrinsic activity ? E D+R

  44. According occupation theory k1 D+R DR- - E k2 [D][R] k2 KD [DR] k1

  45. KD 当全部受体被占领时,效应达最大值Emax,当50%受体与药物结合时, KD=〔D〕 药物与受体的亲和力 The affinity is defined by the dissociation constant(解离常数) which is given the symbol KD. Thehigher the KD, the lower the affinity. (反比)

  46. pD2 affinity index 亲和力指数 pD2 -lgKD KD can be expressed without using mol units. pD2 and affinity are in direct ratio(呈正比) .

  47. 内在活性 与 效能 intrinsic activity & efficacy 药物与受体结合后激动受体的能力。内在活性与药物的效能成正比。常用α表示,0≦ α≦1。

  48. 亲和力与内在活性 E (%) a b c pD2 -lgC 亲和力:a=b=c 内在活性:a﹥b﹥c

  49. E (%) 100 x y z 50 pD2x pD2y pD2z 亲和力:x﹥y﹥z 内在活性:x=y=z

  50. ♥ classification of drugs acting on the receptor 1、agonist (激动药) Full agonists: 1)high affinity 2)high efficacy (i.e. =1).

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