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بسم الله الرحمن الرحيم

بسم الله الرحمن الرحيم. AUTONOMIC NS DRUGS (2) Dr: Samah Gaafar Al- shaygi. ADRENERGIC AGONIST. DIRECT ACTING ADRENERGIC AGONIST: Epinepherine : Synthesized in the adrenal medulla. At low doses has β vasodilatation effect. At high doses has α vasoconstriction effect. Action:

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بسم الله الرحمن الرحيم

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  1. بسم الله الرحمن الرحيم AUTONOMIC NS DRUGS (2) Dr: SamahGaafar Al-shaygi

  2. ADRENERGIC AGONIST • DIRECT ACTING ADRENERGIC AGONIST: • Epinepherine: • Synthesized in the adrenal medulla. • At low doses has β vasodilatation effect. • At high doses has α vasoconstriction effect. • Action: • CVS: β1 +veinotropic & chronotropic effect, COP & O2 demand. • Renal: β1 Renin release, blood flow is decreased.

  3. Blood vessels: α1constrict arterioles to skin, mucous membranes & viscera. β 2 dilate vessels to liver & muscles. • Respiratory: β2 bronchodilataion. • Hyperglycemia: β2 increases glycogenolysis & glucagon secretion. • α2 decrease release of insulin. • Lipolysis.

  4. P.kinetics: • Rapid onset & short duration of action. • Metabolized by MAO & COMT into metanephrine & venillymandilic acid. • i.m, i.v, s.c, inhalation & endotracheal.

  5. Therapeutic uses: • Emergency bronchospasm.choice • Anaphylactic shock.choice • Cardiac arrest. • Anesthesia. • Control bleeding from mucous membranes. • A.E: • CNS disturbances. • Hemorrage. • Cardiac arrythmia. • Pulmonary oedema.

  6. NOREPINEPHERINE: • Is the neurotransmiter. Therapeuticaaly has α activity. • action: • CVS: • Vasoconistriction. • Baroreceptor reflex. • If atropin is given first it inhibits the vagus so N.e causes tachycardia. • P.kinetics: • i.v, poor s.c absorption, short duration of action.

  7. Therapeutic uses: • Only in shock. • A.E: as epi.+ extravasation. • ISOPROTERENOL: • β receptors. • Action: • CVS: • Heart: +veino & chronotrpic effect. • Peripheral vasodilationβ2, slight increase in SBP due to action on heart.

  8. pulmonary stopped, metabolic action. • Used in cardiac arrest. • A.E: as epi. • DOPAMINE: • High doses α1 • Low doses β1 • D1, D2 in mesenteric & renal vascular bed vasodilation.

  9. Action: • CVS: +veinotropic & chronotropic effect, vasoconistriction. • Renal & splanhinic vasodilatation. Therapeutic uses: • In cardiogenic & septic shock, hypotension, severe CCF with oliguria. • Metabolized by MAO & COMT to homovanillic acid. • A.E as sympathetic stimulation.

  10. Dobutamine: • Selective β1 agonist used to COP in CCF & inotropic support after cardiac surgery. • Phenylepherine: • α1 agonist, rasis the BP, reflex bradycardia. • Used topically as nasal decongestant & for ocular mydriasis. • Used in SVT. • A.E hypertensive headache &arrythmias.

  11. Albuterol & terbutaline: • Short acting β2 agonist, used as bronchodilators. • A.E tremor, interaction with MAOIs. • Salmeterol & formoterol: • Long acting β2 agonist. • Used with steroid mainly for nocturnal asthma.

  12. INDIRECT ACTING ADRENERGIC AGONISTS • Enhances the release of epi. Presynaptically or inhibit the uptake. • AMPHETAMINE: • Acts on α1 so BP. • On β stimulates the heart.Note • ADHS, appetite control, narcolepsy. • TYRAMINE: • Normal byproduct of tyrosine. • Oxidized by MAOI in the gut. • COCAINE: • Inhibits the reuptake. • α1 β effects.

  13. MIXED ACTION ADRENERGIC AGONIST • EPHEDRINE & PSEUDOEPHEDRINE: • Long duration of action (poor COMT & MAO substrates). • Ephedrine • increases BP by systoilc & diastolic BP & cardiac stimulation. • CNS stimualtion. atheletic performance. • Pseudoehedrine:nasal,sinus decongestion.

  14. ADRENER α GIC ANTAGONIST • α ADRENERGIC BLOCKING AGENT • Mainly affecting the BP. • Reflex tachycardia. • Phenoxybenzamine: • Acts on α1 & α2 receptors. • peripheral resistance, reflex tachycardia, COP & restore the decrease in BP. • Obsolete in hypertension management. • It’s an epinephrine reversal. • Used in pheochromocytoma, Raynaud disease.

  15. A.E: nasal stiffness, hypotension. • Contraindicated in patients with coronary perfusion. • PHENTOLAMINE: • Action as phenoxybenzamine. • Used for • short treatment of pheochromocytoma. • Norepinephrine administration. • Hypertensive crisis with clonidine & tyramine- MAOI.

  16. Selective α1 inhibitors • prazosin, doxazosin, tamsulosin. • Used for: HTN, CCF, BPH. • A.E: nasal congestion, headache, orthostatic hypotension.

  17. Β-adrenergic blocking agent • All are competitive antagonist. • Act on both β1 & β2 or are selective β1. • Non-selective antagonists: • Propranolol: • CVS: COP, work, O2 consumption. • Blocks β2 peripheral vasodilatation (no postural hypotension). • Bronchoconstriction. • Hypoglycemia.

  18. P.K: • First-pass effect, Cross BBB. • Uses: • HTN. • Hyperthyroidism. • Angina pectoris. • M.I. • A.E: • bronchoconstriction, arrythmias, drug interactions. • Timolol in chronic open-angle glucoma.

  19. Selective antagonist β1 • Atenolol, metoprolol, bisoprolol. • HTN, diabetes, asthma. • Antagonist with partial agonist activity: • E.gpindolol & acebutolol. • Hypertensive with moderate bradycardia, DM. • Antagonist of both α & βarenoreceptors: • Labetalol, carvedilol. • Produce peripheral vasodilatation. • HTN, PIH, HF.

  20. Drugs affecting neurotransmitter release or uptake • resrpine: move dopamine, serotonin & NE into the vesicles. • Guanethidine: displaces NE from the vesicles. • Cocaine: inhibits reuptake.

  21. Thank you

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