- أول مستوى دواء علم
. دماج أمين محمد د
SympathomimeticsDefinition
Drugs that stimulate adrenoceptors and produce actions similar to sympathetic system
1-Catecholamines 2-Non catecholamines
A-Natural B-Synthetic
1-dopamine
2-nor adrenaline
3-adrenalin
1 -isoprenaline
2-dobutamine
3-isoetharine.
1-Ephedrine,
2-amphetamine,
3-phenylephrine
4-salbutamol.
Mechanism of action of sympathomimetics
A-Direct
1-catecholamines
2-phenylephrine
3-salbutamol
1 -Amphetamine
2-Tyramine
1-Ephedrine.
B-Indirect C-Mixed (dual)
Catecholamine drugs
1-Adrenaline :
Mechanism of action
Stimulates directly all types of receptors α – β Administration of adrenaline
S.C , Inhalation , Intra-cardiac , Eye drops.
Action of adrenaline
Uses of adrenaline(indications)
1. In allergy (anaphylactic shock).
2.With local anesthetics.
3.Epistaxis (locally).
4.Hypoglycemia.5.Glaucoma (dipivifrin is better , a prodrug).
6. Cardiac arrest (intracardiac).
7.Acute bronchial asthma.
Contraindications of adrenaline :-
1. Hypertension.
2.Arrhythmia .3.Angina pectoris .
4.Thyrotoxicosis .
5. With local anesthetics in fingers & toes → gangrene .
6.With digitalis and some general anesthetics as halothane → arrhythmias.
7. With non selective β-blockers → severe hypertension.
2-Noradrenaline
Mechanism of action
Stimulates directly α-β1 , β3 no β2
Administration of Noradrenaline
I.V. infusion.
Uses of adrenaline(indications)
1-Acute hypotension Infusion( should not be stopped suddenly).
3-Isoprenaline (isoproterenol)
Mechanism of action
Stimulates directly β1 , β2, β3 but no α-effct
Administration of Iso prenaline.
- Sublingual, Inhalation
Uses of Isoprenaline(indications)
1-Heart block.
2-Acute bronchial asthma.
4-Dopamine
Mechanism of action
Stimulates directly D1 , β1 , α receptors.
Administration of dopamine
I.V. infusion. It can't pass to brain.
Small dose → ↑ D1 → V.d. of renal & mesenteric vessels .
Moderate dose →↑ D1 and β1 ↑ H.R., ↑ C.O., ↑ systolic pressure .
Large dose → α1 V.C.,↑T PR., BP.
Uses of Dopamine (indications)
1-Hypovolemic, cardiogenic &endotoxin shock with correction of hypervolemia.
5-Dobutamine
Mechanism of action
Stimulates directly β1 receptors
Administration
I.V. infusion Uses of Dobutamine (indications)
1-acute heart failure (cardiogenic shock).
6-Fenoldopa- D1 receptor agonist which decreases P.R. by dilating arterioles.
- It is given by I.V. drip in emergency hypertension.
Side effects :
1-Headache, 2-Flushing 3-Tachycardia.
1-Non-Catecholamines drugs
A)β – stimulants B)α – stimulants
1-Selective β2 agonistsEx. Salbutamol
3-Non Selective β agonistsEx. Adrenaline
1-Selective α1 agonistsEx. Phenylephrine
2-Selective α2 agonistsEx. Clonidine
2 -Selective β1 agonistsEx. Dobutamine
3-Non Selective α agonistsEX. Adrenaline , Noradrenaline
1-Selective β2 agonists
A) β – stimulants
3-Non selective β-agonists
1-Salbutamol (ventolin)
2-terbutalin (Bricanyl 3-salmetrol (Serevent)
4-formoterol (foradil )
2- selective β1-agonists
Action of selective β2 agonist1- Produce broncho dilatation,
2- ↓ bronchial secretions & ↓ release of allergic mediators from mast cells.
3- Relax uterus & produce V.D.
4- ↓ B.P. & produce mild tachycardia (reflex and weak
β1 effect).
5- ↑ glycogenolysis& insulin release .
Clinical Uses 1 -in bronchial asthma. (acute attack & prophylaxis).
Side effects:- 1 -Tremors 2-tachycardia 3 -nervousness.
Ritodrine -: β2 agonist, used in
1- premature labour
2-constriction ring of uterus
3- dysmenorrhea.
Non selective β-agonists
1-Isoxsuprine 2-Oriciprenaline
Used in 1-vascular disease
2-constriction ring of uterus.
Used orally or inhalation in bronchial
asthma
B) α – stimulants
1-Selective α1 agonistsEx. Phenylephrine
2-Selective α2 agonistsEx. Clonidine
2-Non Selective α agonists
EX. Adrenaline , Noradrenaline
1-Phenylephrine oral, local, injection.
2-Midodrine oral (prodrug).
3-Methoxamine injection.
Action of Selective α1 agonist1-Produce V.C. → decongestant
2 -↑P.R ,.3 -↑B.P. (systolic & diastolic). → reflex
bradycardia4-Active mydriasis (+ ve L.R.).
Clinical Uses1. Treatment of hypotension.
2.Treatment of Paroxysmal Atrial Tachycardia ( PAT).
3.mydriatic& decongestant (phenylephrine).
Nasal decongestant
A)Local B)Systemic (oral)
1. Naphazoline (Privin)
2. Xylometazoline (otrivin, Rhinex , Balkis)
3. Tetrahydrozoline(Nazine)
4. Oxymetazoline (Afrin ,oxymet)
Non –irritant nasal drops and sprays (less rebound congestion).
B)Systemic (oral)
1-Phenylpropanolamine (coldact,Flustop ,Eskornade).
2-Pseudoephedrine.(Actifed ,Histarhine,Doldex-2):oral common cold preparation
3-Phenylephrine (α1 agonist).(Noflu , Sine –up): oral
common cold preparation
THANK YOU Dr. Mohammad dammage
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