الرحيم الرحمن الله بسم

AUTONOMIC NS

DRUGS (2)Dr: Samah Gaafar Al-shaygi

ADRENERGIC AGONISTDIRECT ACTING ADRENERGIC AGONIST:1. Epinepherine: Synthesized in the adrenal medulla. At low doses has β vasodilatation effect. At high doses has α vasoconstriction effect. Action:1. CVS: β1 +ve inotropic & chronotropic

effect, COP & O2 demand. 2. Renal: β1 Renin release, blood flow is

decreased.

3. Blood vessels: α1 constrict arterioles to

skin, mucous membranes & viscera. β 2 dilate vessels to liver & muscles.

4. Respiratory: β2 bronchodilataion.5. Hyperglycemia: β2 increases

glycogenolysis & glucagon secretion. α2 decrease release of insulin.

6. Lipolysis.

P.kinetics:Rapid onset & short duration of action.Metabolized by MAO & COMT into

metanephrine & venillymandilic acid.i.m, i.v, s.c, inhalation & endotracheal.

Therapeutic uses:Emergency bronchospasm.choiceAnaphylactic shock.choiceCardiac arrest.Anesthesia.Control bleeding from mucous membranes.

A.E:CNS disturbances.Hemorrage.Cardiac arrythmia.Pulmonary oedema.

NOREPINEPHERINE:Is the neurotransmiter. Therapeuticaaly has α

activity. action:1. CVS:

1. Vasoconistriction.2. Baroreceptor reflex.

2. 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.

Therapeutic uses:Only in shock.A.E: as epi.+ extravasation.ISOPROTERENOL: β receptors.Action:1. CVS:

Heart: +ve ino & chronotrpic effect. Peripheral vasodilation β2, slight increase in

SBP due to action on heart.

2. 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.

Action:1. CVS: +ve inotropic & chronotropic effect, vasoconistriction.2. 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.

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.

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.

INDIRECT ACTING ADRENERGIC AGONISTSEnhances the release of epi. Presynaptically or inhibit the

uptake.AMPHETAMINE:Acts on α1 so BP.On β stimulates the heart. NoteADHS, appetite control, narcolepsy.TYRAMINE:Normal byproduct of tyrosine.Oxidized by MAOI in the gut.COCAINE:Inhibits the reuptake.α1 β effects.

MIXED ACTION ADRENERGIC AGONISTEPHEDRINE & 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.

ADRENER α GIC ANTAGONISTα ADRENERGIC BLOCKING AGENTMainly 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.

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.

Selective α1 inhibitorsprazosin, doxazosin, tamsulosin.Used for: HTN, CCF, BPH.A.E: nasal congestion, headache, orthostatic

hypotension.

Β-adrenergic blocking agentAll 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.

P.K:First-pass effect, Cross BBB.Uses:

1. HTN.2. Hyperthyroidism.3. Angina pectoris.4. M.I.

A.E: bronchoconstriction, arrythmias, drug

interactions. Timolol in chronic open-angle glucoma.

Selective antagonist β1Atenolol, metoprolol, bisoprolol.HTN, diabetes, asthma.Antagonist with partial agonist activity:E.g pindolol & acebutolol.Hypertensive with moderate bradycardia,

DM.Antagonist of both α & β arenoreceptors:Labetalol, carvedilol.Produce peripheral vasodilatation.HTN, PIH, HF.

Drugs affecting neurotransmitter release or uptakeresrpine: move dopamine, serotonin & NE

into the vesicles.Guanethidine: displaces NE from the vesicles.Cocaine: inhibits reuptake.

Thank you