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Flashcards in Sympathomimetics Deck (116)
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1

 Constitute a group of drugs used for
Cardiovascular
Respiratory
Other conditions

adrenomimetics

2

Type of adrenomimetics based on mode of action
 Bind to and activate the adrenoceptors
 Result to sympathetic stimulation

DIRECT-ACTING SYMPATHOMIMETICS

3

INDIRECT-ACTING SYMPATHOMIMETICS
 Displacement of stored cathecolamines in the synapse

releasers

4

example of releasers

tyramine, amphetamine

5

INDIRECT-ACTING SYMPATHOMIMETICS
Inhibit the reuptake of cathecolamines by nerve terminals

Reuptake inhibitors

6

example of Reuptake inhibitors

Cocaine, tricyclic antidepressants

7


 Constitute a third class of adrenoceptors
 Drugs mentioned have little effect on dopamine receptors
 May act as a potent dopamine receptor agonist itself
 Intermediate doses activate beta receptors
 Large doses activate alpha receptors

DOPAMINE

8

dopamine
Intermediate doses activate -- receptors

beta

9

dopamine
Large doses activate --receptors

dopamine

10



 Drug preferentially binds to one subgroup of receptors at concentrations too low to interact with another receptor

RECEPTOR SELECTIVITY

11

 Parent compound of sympathetic drug

phenylethylamine

12

effect of Increasing the size of alkyl substituents

Enhanced activity for beta 2 receptors
Lowers alpha receptor activity

13

 Methyl substitution on NE yields ----
Effect:
Enhanced activity for beta 2 receptors

epinephrine
Effect: Enhanced activity for beta 2 receptors

14

 Isopropyl substitution on NE yields

isoproterenol

15

 -OH groups at the C? and C? positions yield cathecolamines

c3 and c4

16

effect of  Absence of one or both –OH group

Increases bioavailability after oral administration
 COMT resistant
 Increase distribution to the CNS
 Amphetamine and ephedrine

17

effect of C. Substitution on the alpha carbon
 Add methyl group

MAO resistant
Amphetamine and ephedrine

18

effect of D. Substitution on the beta carbon
 Add OH group

Facilitates activation of adrenoceptors
For storage of cathecolamines
Direct-acting sympathomimetics
Dopamine does not contain beta-OH group

19

does dopamine contain a beta-OH group

Dopamine does not contain beta-OH group

20

comparative competency for alpha receptors

E > NE> isoproterenol

21

receptor responsible for
Increase in phosphatidyl inositol (IP3)
Release of calcium

alpha 1

22

receptor responsible for decrease cAMP

D1 and alpha 2

23

comparative competency BETA RECEPTOR ACTIVATION

Isoproterenol > epinephrine > NE

24

receptors responsible for increase cAMP

B1, B2, B3

25

Penetrates the CNS producing stimulant effects

Amphetamine

26

ORGAN SYSTEM EFFECTS
B. EYE

Pupillary dilator responds with mydriasis
 Accommodation is not significantly affected
 Alpha agonists reduce intraocular pressure by increasing outflow of aqueous humor

27

---- agonists reduce intraocular pressure by increasing outflow of aqueous humor

Alpha

28

ALPHA agonists reduce intraocular pressure by

increasing outflow of aqueous humor

29

EFFECT OF BETA ANTAGONISTS IN AQUEOUS HUMOR

 Beta antagonists decrease production of aqueous humor

30

ORGAN SYSTEM EFFECTS
BRONCHI

C. BRONCHI
 Marked relaxation of the smooth muscles of the bronchi
 Most efficacious and reliable for reversing bronchospasm

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