The document provides an overview of sympathomimetic drugs, which stimulate adrenoceptors and produce actions similar to the sympathetic system. It details the classification of these drugs into catecholamines and non-catecholamines, their mechanisms of action, and various clinical uses and contraindications for drugs like adrenaline, noradrenaline, dopamine, and dobutamine. Additionally, it covers selective and non-selective β and α agonists, their effects, side effects, and clinical applications in treating conditions such as asthma, shock, and hypotension.

1. -
‫أول‬ ‫مستوى‬ ‫دواء‬ ‫علم‬
.
‫دماج‬ ‫أمين‬ ‫محمد‬ ‫د‬

2. Sympathomimetics
Definition
Drugs that stimulate adrenoceptors and produce
actions similar to sympathetic system

3. 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.

4. Mechanism of action of sympathomimetics
A-Direct
1
-
catecholamines
2
-
phenylephrine
3
-
salbutamol
1
-
Amphetamine
2
-
Tyramine
1
-
Ephedrine
.
B-Indirect C-Mixed (dual)

5. 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

6. 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
.

7. 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.

8. 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).

9. 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
.

10. 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.

11. Uses of Dopamine (indications)
1-Hypovolemic,
cardiogenic &endotoxin
shock with correction of
hypervolemia.

12. 5-Dobutamine
Mechanism of action
Stimulates directly β1 receptors
Administration
I.V. infusion
Uses of Dobutamine (indications)
1
-
acute heart failure (cardiogenic shock)
.

13. 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.

14. 1-Non-Catecholamines drugs
A)β – stimulants B)α – stimulants
1
-
Selective β2 agonists
Ex. Salbutamol
3
-
Non Selective β agonists
Ex. Adrenaline
1
-
Selective α1 agonists
Ex. Phenylephrine
2
-
Selective α2 agonists
Ex. Clonidine
2
-
Selective β1 agonists
Ex. Dobutamine
3
-
Non Selective α agonists
EX. Adrenaline , Noradrenaline

15. 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

16. Action of selective β2 agonist
1- 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 .

17. 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.

18. 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

19. B) α – stimulants
1
-
Selective α1 agonists
Ex. Phenylephrine
2
-
Selective α2 agonists
Ex. Clonidine
2
-
Non Selective α
agonists
EX. Adrenaline , Noradrenaline
1-Phenylephrine oral, local, injection.
2-Midodrine oral (prodrug).
3-Methoxamine injection.

20. Action of Selective α1 agonist
1
-
Produce V.C. → decongestant
2
-
↑
P.R
,.
3
-
↑
B.P. (systolic & diastolic). → reflex
bradycardia
4-Active mydriasis (+ ve L.R.).
Clinical Uses
1. Treatment of hypotension.
2.Treatment of Paroxysmal Atrial Tachycardia ( PAT).
3.mydriatic& decongestant (phenylephrine).

21. 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).

22. 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

23. THANK YOU
Dr. Mohammad dammage