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Flashcards in SYMPATHOMIMETICS Deck (48):
1


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

Adrenomimetics

2

Adrenomimetics
Subdivided into:
 Mode of action

Direct-acting
 Indirect-acting

3

Adrenomimetics
Subdivided into:
 Spectrum of action

 Alpha
 Beta
 Dopamine receptor affinity

4

A. MODE OF ACTION

 Bind to and activate the adrenoceptors
 Result to sympathetic stimulation

DIRECT-ACTING SYMPATHOMIMETICS

5

A. MODE OF ACTION

 Displacement of stored cathecolamines in
the synapse
 Tyramine, amphetamine

INDIRECT-ACTING SYMPATHOMIMETICS

6

A. MODE OF ACTION

 Inhibit the reuptake of cathecolamines by
nerve terminals
 Cocaine, tricyclic antidepressants

INDIRECT-ACTING SYMPATHOMIMETICS

7


 Present in the mitochondria in the adrenergic nerve endings
 Inactivates portion of dopamine and norepinephrine in the cytoplasm

MONOAMINE OXIDASE (MAO)

8


 May increase the stores of these transmitters and other amines in
the nerve endings

MONOAMINE OXIDASE INHIBITORS

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subgroups of alpha

alpha 1
alpha 2

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subgroups of beta

beta 1
beta 2
beta 3

11


 Single prototype with effects at all receptors
 Alpha1 and alpha2
 Beta1,beta2 and beta3

EPINEPHRINE

12

 Separate prototype
 Alpha

PHENYLEPHRINE

13


 Separate prototype
 Beta
 Synthetic cathecolamine
 Similar to the endogenous transmitters
 Not readily taken up into the nerve ending

ISOPROTERENOL

14

B. SPECTRUM OF ACTION

 Constitute a third class of adrenoceptors
 Drugs mentioned have little effect on
dopamine
 May act as a potent dopamine receptor
agonist itself

DOPAMINE

15


 Epinephrine, norepinephrine, and dopamine
 Endogenous adrenoceptor agonists
Rapidly metabolized by COMT and MAO
 Inactive when given by the oral route
 Short duration of action
 When given IV, they do not enter the CNS
in significant amounts

CATHECOLAMINES

16


 Not a cathecolamine
 Resistant to MAO
 Resistant to COMT
 Orally active
 Enter the CNS
 Longer effects

AMPHETAMINES

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 Presence of OH groups at carbons 3 and 4
 Degraded by cathecol-o-methyl transferase
(COMT)

PHENYLETHYLAMINE

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PHENYLETHYLAMINE
 Removal of OH will:

 Make it resistant to COMT
 Prolong the duration of action
 Increase bioavailability
 Increase the ability to penetrate the CNS

19


 Alter the alpha carbon, add CH3
Phenylisopropylamine
Ephedrine, amphetamine

PHENYLETHYLAMINE

20

 Alter the beta carbon, add OH
Direct-acting
Important in the storage of cathecolamines

PHENYLETHYLAMINE

21


 G-protein coupled
 Need a 2nd messenger to induce
sympathetic effect

ADRENOCEPTORS

22


 Epinephrine > NE > isoproterenol
 Alpha1
 Increase in phosphatidyl inositol (IP3)
 Release of calcium
 Alpha2

ALPHA RECEPTOR ACTIVATION

23


 Receptors found in renal vasculature, brain

DOPAMINE RECEPTOR ACTIVATION

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beta1 = beta2

DOBUTAMINE
ISOPROTERENOL

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beta2 > beta1

TERBUTALINE

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ADRENOCEPTORS
ALPHA SELECTIVE
alpha1 > alpha2
alpha1 activation

 PHENYLEPHRINE

27

ADRENOCEPTORS
ALPHA SELECTIVE
alpha2 > alpha1
alpha2 activation

 CLONIDINE

28

ADRENOCEPTORS
MIXED (activates both alpha and beta)
alpha1 = alpha2
beta1 > beta2
 EPINEPHRINE alpha1 = alpha2
beta1 = beta2

 NE

29

ADRENOCEPTORS
MIXED (activates both alpha and beta)

alpha1 = alpha2
beta1 = beta2

 EPINEPHRINE

30

CLINICAL USES
A. ANAPHYLAXIS

 Drug of choice for the immediate
treatment of anaphylactic shock
 Rapid acting
 Pressor agent
 Used for cardiac arrest

EPINEPHRINE

31

B. CNS

 Narcolepsy
 Attention deficit disorder
 With appropriate control, weight
reduction

PHENYLISOPROPYLAMINES
(AMPHETAMINES)

32

CLINICAL USES
C. EYE

 Used topically to produce mydriasis
 Used to reduce conjunctival itching
and congestion caused by irritation
and allergy

PHENYLEPHRINE

33

D. BRONCHI

 Drugs of choice in the treatment of
acute asthmatic attacks

TERBUTALINE, ALBUTEROL, METAPROTERENOL

34

CLINICAL USES
D. BRONCHI

 Long-acting
 Recommended for prophylaxis

SALMETEROL

35

CLINICAL USES
F. GUT

 Long-acting oral sympathomimetic used
to improve urinary incontinence in children
and the elderly with enuresis
 Mediated by the alpha receptors in the
trigone of the bladder

EPHEDRINE

36

CATHECOLAMINES

 Pressor agent
 Cardiac arrest
 Anaphylactic shock

EPINEPHRINE

37

CATHECOLAMINES

 Pressor agent
ISOPROTERENOL
 Cardiogenic shock

NOREPINEPHRINE

38

CATHECOLAMINES

 Cardiogenic shock

ISOPROTERENOL

39

CATHECOLAMINES

 Congestive heart failure
 Inotropic effect

DOBUTAMINE

40

CATHECOLAMINES

 Inotropic effect
 Lower doses cause renal vasodilation
 Higher doses cause vasoconstriction

DOPAMINE

41

NON-CATHECOLAMINES
 Pressor agent
 Mydriatic
 Decongestant

PHENYLEPHRINE

42

NON-CATHECOLAMINES

 Pressor agent
 IV form only

METHOXAMINE

43

NON-CATHECOLAMINES

 Pressor agent
 Orthostatic hypotension

MIDODRINE

44

NON-CATHECOLAMINES

 OXYMETAZOLINE, XYLOMETAZOLINE
 Topical decongestants

DRIXINE

45

NON-CATHECOLAMINES

 Bronchial asthma

TERBUTALINE

46

NON-CATHECOLAMINES

 Inhibits premature labor

RITODRINE

47

NON-CATHECOLAMINES

 Local vasoconstrictive
 Anesthetic effect

COCAINE

48

NON-CATHECOLAMINES

 Derivative of tyrosine
 Increase BP
 Found in cheese and wine

TYRAMINE

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