Flashcards in Sympathomimetics Deck (116):
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
31
Well endowed with both alpha and beta receptors
Located on the smooth muscles and neurons of the enteric nervous system
GIT
32
WHAT ORGAN
Activation of either receptors leads to the relaxation of the smooth muscles
GIT
33
---- agonist causes uterine relaxation in pregnancy
Beta2
34
Responsible for Vasoconstriction
Alpha1 agonists
35
agonists that can reduce PVR and BP
beta2
36
causes vasodilatation in the splanchnic and renal vascular beds
Dopamine
37
Well supplied with beta1 and beta2 receptors
G. HEART
38
increases renin release
Beta1
39
increases insulin secretion (gluconeogenesis)
Beta2
40
Stimulate lipolysis
beta3
41
Drug of choice for the immediate treatment of anaphylactic shock
Rapid acting
Pressor agent
Used for cardiac arrest
EPINEPHRINE
42
Narcolepsy
Attention deficit disorder
With appropriate control, weight reduction
PHENYLISOPROPYLAMINES (AMPHETAMINES)
43
Used topically to produce mydriasis
Used to reduce conjunctival itching and congestion caused by irritation
and allergy
PHENYLEPHRINE
44
Drugs of choice in the treatment of acute asthmatic attacks (3)
TERBUTALINE, ALBUTEROL, METAPROTERENOL
45
Long-acting
Recommended for prophylaxis of asthma
SALMETEROL
46
? agonists maybe useful in situations like Acute cardiac failure, Some types of shock
Beta1
47
? agonists are useful in situations in which vasoconstriction is needed
Alpha1
48
Used to suppress premature labor
Cardiac stimulant effect may be hazardous to both mother and fetus
RITODRINE, TERBUTALINE
49
Long-acting oral sympathomimetic usedto improve urinary incontinence in children and the elderly with enuresis
Mediated by the alpha receptors in the trigone of the bladder
EPHEDRINE
50
Pressor agent
Cardiac arrest
Anaphylactic shock
EPINEPHRINE
51
Potent vasodilator
ISOPROTERENOL
52
Congestive heart failure
Inotropic effect
DOBUTAMINE
53
Inotropic effect
Lower doses cause renal vasodilation
Higher doses cause vasoconstriction
DOPAMINE
54
catecholamines
dopamine, dobutamine, isoproterenol, epinephrine, norepinephrine
55
Pressor agent
Mydriatic
Decongestant
PHENYLEPHRINE
56
Pressor agent, limited clinical application
IV form only
METHOXAMINE
57
Pressor agent
Orthostatic hypotension
MIDODRINE
58
DRIXINE (brand name)
Topical decongestants
OXYMETAZOLINE, XYLOMETAZOLINE
59
Bronchial asthma
TERBUTALINE
60
Inhibits premature labor
RITODRINE
61
Local vasoconstrictive
Anesthetic effect
COCAINE
62
Byproduct of tyrosine
Increase BP
Found in fermented food
Cheese and wine
TYRAMINE
63
Not advised for patients taking MAO inhibitors
TYRAMINE
64
Toxicity of sympathomimetic drugs speciifically endogenous catecholamines
Limited penetration to the brain
Little CNS toxicity when given systemically
In the periphery
65
Toxicity in the peripheral vasculature
Excessive vasoconstriction
Cardiac arrhythmias
Myocardial infarction
Pulmonary edema or hemorrhage
66
? agonists cause hypertension
Alpha
67
? agonists cause sinus tachycardia
and serious arrhythmia
Beta1
68
? agonists cause skeletal muscle tremor
Beta 2
69
? agonists cause skeletal muscle tremor
Beta 2
70
α1 Most vascular smooth muscle
Contracts (↑ vascular resistance)
71
Pupillary dilator muscle
α1
Contracts (mydriasis)
72
Pilomotor smooth muscle
α1
Contracts (erects hair)
73
Liver (in some species, eg, rat)
α1
Stimulates glycogenolysis
74
Adrenergic and cholinergic nerve terminals
Inhibits transmitter release
75
Platelets α2
Stimulates aggregation
76
Some vascular smooth muscle α2
Contracts
77
Fat cells α2
Inhibits lipolysis
78
α2
Pancreatic β (B) cells
Inhibits insulin release
79
β1 Heart
Stimulates rate and force
80
β1Juxtaglomerular cells of kidney
Stimulates renin release
81
Beta 2 Airways, uterine, and vascular smooth muscle
Relaxes
82
Liver (human) Beta 2
Stimulates glycogenolysis
83
Pancreatic β (B) cells Beta 2
Stimulates insulin release
84
Somatic motor neuron terminals (voluntary muscle) Beta 2
Causes tremor
85
Heart Beta 2
Stimulates rate and force
86
β3 Fat cells
Stimulates lipolysis
87
Dopamine1 (D1) Renal and other splanchnic blood vessels
Dilates (↓ resistance)
88
Dopamine2 (D2) Nerve terminals
Inhibits adenylyl cyclase
89
mechanism of action of E
α1, α2, β1, β2, β3 agonist
90
mechanism of action of NE
α1, α2, β1, agonist
91
mechanism of action of Dopamine
D1, α1, α2, β1, β2, β3 agonist
92
mechanism of action of Isoproterenol:
β1, β2, β3 agonist;
93
mechanism of action of Dobutamine:
β1 agonist
94
mechanism of action of PHENYLEPHRINE
α1, α2 agonist
95
mechanism of action of Albuterol, metaproterenol, terbutaline
β2 agonist
96
Displaces stored
catecholamines from nerve
endings
Amphetamine,
methamphetamine
97
Very high addiction
liability. Hypertension,
arrhythmias, seizures
COCAINE
98
Displaces stored catecholamines
No clinical use but found in fermented foods
TYRAMINE
99
An α-agonist drug that reduces conjunctival, nasal, or oropharyngeal mucosal
vasodilation by constricting blood vessels in the submucosal tissue
decongestant
100
A derivative (eg, norepinephrine, epinephrine), a relatively
polar molecule that is readily metabolized by catechol-O-methyltransferase
Catecholamine
101
catecholamine is derived from
dihydroxyphenylethylamine
102
A derivative of phenylisopropylamine (eg, amphetamine, ephedrine). Unlike
catecholamines, they usually have oral activity, a long half-life,
CNS activity, and cause release of stored catecholamines
Phenylisopropylamine
103
A drug that mimics stimulation of the sympathetic autonomic nervous system
Sympathomimetic
104
An indirect-acting drug that increases the activity of transmitters in the synapse by
inhibiting their reuptake into the presynaptic nerve ending. May act selectively on
noradrenergic, serotonergic, or both types of nerve endings
Reuptake inhibitor
105
Present in the mitochondria in the adrenergic nerve endings
Inactivates portion of dopamine and norepinephrine in the cytoplasm
MONOAMINE OXIDASE (MAO)
106
May increase the stores of these transmitters and other amines in
the nerve endings
MONOAMINE OXIDASE INHIBITORS
107
Single prototype with effects at all receptors
Alpha1 and alpha2
Beta1,beta2 and beta3
EPINEPHRINE
108
Not a cathecolamine
Resistant to MAO
Resistant to COMT
Orally active
Enter the CNS
Longer effects
AMPHETAMINES
109
Signaling mechanism of adrenoceptors
G-protein coupled
Need a 2nd messenger to induce
sympathetic effect
110
ALPHA SELECTIVE
alpha1 > alpha2
PHENYLEPHRINE
111
ALPHA SELECTIVE
alpha2 > alpha1
CLONIDINE
112
MIXED (activates both alpha and beta)
alpha1 = alpha2
beta1> beta2
NE
113
MIXED (activates both alpha and beta)
alpha1 = alpha2
beta1 = beta2
EPINEPHRINE
114
beta1 > beta2
DOBUTAMINE
115
beta2 > beta1
TERBUTALINE
116