Flashcards in SYMPATHOMIMETICS Deck (48)
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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
9
subgroups of alpha
alpha 1
alpha 2
10
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
17
Presence of OH groups at carbons 3 and 4
Degraded by cathecol-o-methyl transferase
(COMT)
PHENYLETHYLAMINE
18
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
24
beta1 = beta2
DOBUTAMINE
ISOPROTERENOL
25
beta2 > beta1
TERBUTALINE
26
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
