Adrenergic Drugs Flashcards
(82 cards)
1
Q
Alpha 1 receptor subtype location
A
a - prostate
radial muscles, bladder sphincters, skin, blood vessels
2
Q
Dopamine receptor location
A
Renal and mesenteric blood vessels
3
Q
Alpha 1 receptor stimulation effect
A
Constriction
4
Q
Dopamine receptor stimulation effect
A
Dose dependent
Low dose - vasodilation
High dose - stimulation of alpha 1 and beta 1 receptors - increase cardiac output and contractility, increase NE release at heart synapse by blocking reuptake
5
Q
Alpha 1 receptor mechanism
A
Gq - phospholipase C coupling (PIP2 to IP3 and DAG) - increase Ca2+
6
Q
What cholinergic receptor has the same mechanism as the adrenergic alpha 1 receptors?
A
M3
7
Q
Alpha 2 receptor subtype location
A
a - vasomotor center, SNS and PSNS postganglionic fibers
b - vascular smooth muscle
8
Q
Alpha 2 receptor subtype mechanism
A
Gi - inhibition of adenylyl cyclase, decrease CAMP levels
9
Q
Dopamine receptor mechanism
A
Gs - stimulate adenylyl cyclase, increase CAMP levels
10
Q
Alpha 2a receptor effect
A
- Vasomotor center - decrease SNS outflow to heart (decrease contractility), vasculature (decrease TPR), and adrenal medulla (decrease levels of epi/norepi)
- Postsynaptic SNS ganglionic fibers - feedback inhibition through NE hyperpolarization which decreases further NE release
- Postsynaptic SNS-PSNS meets - “collaterols” NE on alpha 2a on cholinergic fibers decreases ACh release and Ach on muscarinic on adrenergic fibers decreases NE release
11
Q
What receptors ensure that the SNS and the PSNS are not exerting opposing effects at the same time?
A
Alpha 2a
12
Q
Beta 1 receptor location
A
Heart and kidney
13
Q
Alpha 2 receptor NT affinity
A
E»>NE
14
Q
Beta 1 receptor NT affinity
A
E=NE
15
Q
Beta 2 receptor NT affinity
A
E»>NE
16
Q
Beta 3 receptor NT affinity
A
NE»>E
17
Q
Beta 3 receptor NT affinity
A
NE»>E
18
Q
Beta 1 receptor mechanism
A
Gs - stimulate adenylyl cyclase, increase CAMP levels
19
Q
Beta 2 receptor mechanism
A
Gs - stimulate adenylyl cyclase, increase CAMP levels
20
Q
Beta 3 receptor mechanism
A
Gs - stimulate adenylyl cyclase, increase CAMP levels
21
Q
Beta 1 receptor effect
A
Increase heart contractility
Increase renin production to increase blood volume and therefore increase blood pressure
22
Q
Beta 2 receptor location
A
Skeletal and liver blood vessels
Skeletal muscle
Bronchi
Liver
23
Q
Beta 2 receptor effect
A
Skeletal and liver blood vessels - dilation
Skeletal muscle - potassium uptake, glycogen breakdown
Bronchi - dilation
Liver - glycogen breakdown
24
Q
Beta 3 receptor location
A
Bladder
25
Beta 3 receptor effect
Relaxation of detrusor - urinary retention
26
Explain the effects of increase CAMP levels by location. What receptors are involved?
Cardiac muscle - Beta 1 or Beta 2 - contraction
| Smooth muscle - Beta 2, Beta 3, Dopamine - relaxation
27
Which adrenergic receptors are not innervated?
Beta 2
28
What role does phosphodiesterase play in the adrenergic system?
Breakdown to CAMP
29
What is the general effect of PDE inhibitors?
Increase effect of CAMP:
Increase cardiac contractility
Bronchodilation
Vasodilation
30
How can you inhibit the synthesis of catecholamines?
Metyrosine - competitive inhibitor of tyrosine hydroxylase
| NE - feedback inhibition of TH
31
Describe 3 mechanisms by which catecholamine effect is terminated
Reuptake - NET transporter (into cytoplasm) and VMAT (into vesicle)
Degradation - MAO (presynaptic terminal) and COMT (end organ)
Inhibition - alpha 2a
32
What receptor does phenylephrine work on?
alpha 1 agonist
33
What is the effect of histamine?
Vasodilation
34
What 3 drugs can be used to impact catecholamine synthesis?
Metyrosine
L-Dopa
Reserpine
35
Describe metyrosine including the mechanism, effect, and what purpose it is used for
Decrease catecholamine synthesis by competitively inhibiting tyrosine hydroxylase
Treatment of pheochromocytoma (catecholamine-secreting tumor of adrenal medulla)
36
Describe L-Dopa including the mechanism, effect, and what purpose it is used for
Increase catecholamine synthesis
| Treatment of Parkinson's (can cross BBB) and TH deficiency
37
What is a consideration when using L-Dopa as a treatment?
Dopamine in periphery would cause renal vasodilation - give in conjunction with carbidopa which prevents peripheral conversion of L-Dopa to Dopamine
38
Describe reserpine including the mechanism, effect, and what purpose it is used for
Disrupts VMAT - dopa, NE, epi, serotonin do not go into vesicles, destruction by MAO
Treatment of HTN and psychosis historically but caused risk of SI
39
Describe Clonidine including the mechanism, effect, and what purpose it is used for
alpha 2a and 2c agonist, decreases NE via vasomotor center, reduces SNS tone
Treatment of HTN, Tourette's, withdrawl
40
Describe botulinum toxin including the mechanism, effect, and what purpose it is used for
Blocks VAMP and SNAP coupling to block ACh release and prevents muscle contraction
Treatment of muscle spasticity and wrinkles
41
Describe tetanus toxin including the mechanism, effect, and what purpose it is used for
Prevents GABA release by blocking VAMP and SNAP coupling
| Not used in any treatment of disease - causes seizures and prolonged muscle contraction
42
Describe amphetamines including the mechanism, effect, and what purpose it is used for (2 mechanisms)
Blocks VMAT and MAO, which increases cytoplasmic concentration of NE, dopa, and serotonin, prolonging their action - reuptake (NET) transporter reverses and releases NTs
Also prevents reuptake via NET transporter prolonging action of NE, dopa, serotonin
Treatment of ADHD, narcolepsy, and acts as a general stimulant
Potential for abuse due to prolonged dopamine action
43
What is ritalin an example of?
Amphetamine
44
Describe ephedrine including the mechanism, effect, and what purpose it is used for
Increases non-physiologic NE release and weakly stimulates beta receptors
Pseudophedrine (sudafed) is used at OTC nasal decongestant - constricts nasal blood vessels but can lead to rebound hyperemia
45
Why is ephedrine closely regulated over the counter?
Similar to methamphetamine in structure - can be used to make meth
46
Describe tyramine including the mechanism, effect, and what purpose it is used for
Increases non-physiologic NE release - usually is degraded by MAO
Causes HTN in patients on MAO inhibitors
Found in aged foods - cheese, beer, wine
47
Describe cocaine including the mechanism, effect, and what purpose it is used for
Blocks NET transporter which reuptakes NTs - prolongs action of dopa, NE, and serotonin
48
Why is cocaine abuse so dangerous?
Abuse due to effects on dopamine
| Toxicity due to NE overstimulation of the heart
49
Describe desipramine including the mechanism, effect, and what purpose it is used for
Tricyclic anti-depressant
Prolongs NE and serotinin action via inhibition of reuptake but does not affect dopa - less potential for abuse and used as anti-depressant
50
What is an important consideration for patients on MAO inhibitors?
Avoid tyramine-rich foods
51
Name 3 dangerous drug interactions with MAO inhibitors
1. Opioids - potentially fatal via unknown mechanisms
2. Stimulants, anti-depressants, and decongestants - potentially dangerously high levels of NE
3. Serotonin syndrome - excessive serotonin levels in the body
52
Describe phenelzine including the mechanism, effect, and what purpose it is used for
Non-selective MAO inhibitor
| Treatment of depression
53
Describe selegiline including the mechanism, effect, and what purpose it is used for
MAO-B inhibitor - increases dopamine levels
| Used as an adjunctive treatment for Parkinson's
54
What is another name for selegiline?
Deprenyl
55
What is another name for deprenyl?
Selegiline
56
What drugs behave similarly to phenelzine?
Isocarboxazid
| Tranylcypromine
57
What are two specific PDE enzymes and what second messengers do the affect primarily?
PDE-4: breaks down CAMP
| PDE-5: breaks down CGMP
58
Describe aminophylline including the mechanism, effect, and what purpose it is used for
Non-selective PDE inhibitor
| Historical uses in Asthma and COPD (bronchiolar relaxation) but not used anymore due to cardiac side effects
59
What is another name for aminophylline?
Theophylline
60
What is another name for theophylline?
Aminophylline
61
Describe sildenafil including the mechanism, effect, and what purpose it is used for
Selective PDE5 inhibitor - increases levels of CGMP, which promotes smooth muscle relaxation
Treatment of erectile dysfunction - blood to penis
Pumlonary HTN - lung vasodilation
Potential future uses for dementia through increasing cerebral blood flow
62
What are two other drugs that behave similarly to sildenafil?
Vardenafil
| Tadalafil
63
Which adrenergic agonist increases perfusion without increasing HR and why?
Norepi increases perfusion by increasing TPR (DBP) as well as cardiac contractility (SBP) but does not increase HR because the baroreceptor reflex works to counteract increases in HR
64
Why is epi so useful in cardiac arrest and anaphylactic shock?
Acts on B2 receptors in addition to all NE effects - overall decreases in TPR (DBP) with increase in cardiac contractility (SBP) so mean blood pressure remains the same and the baroreceptor reflex is not activated - this significantly increases cardiac output and perfusion
65
Describe the effects of isoproterenol?
Only acts on beta receptors - exaggerated epi response - greater decrease in TPR due to no alpha activation - this actually causes an increase in HR due to baroreceptor reflex, which GREATLY increases CO
66
Describe dobutamine including the mechanism, effect, and what purpose it is used for
Beta 1 agonist - used in acute heart failure by increasing cardiac output - decrease TPR and heart rate - makes the heart more efficient
67
Describe albuterol including the mechanism, effect, and what purpose it is used for
Beta 2 agonist - used in asthma for bronchodilation without severe cardiac effects (only 20% heart is beta 2)
68
What class of drugs was investigated for potential effects in uterine contractions and what was the implication?
Beta 2 agonist - highlighted hormonal expression of receptors
69
Describe phenylephrine including the mechanism, effect, and what purpose it is used for
Alpha 1 agonist - increases BP through vasoconstriction and lowers HR via baroreceptor reflex
70
Describe brimonidine including the mechanism, effect, and what purpose it is used for
Alpha 2 agonist - decreases intra-ocular pressure by decreasing production of aqueous humor
Treatment of glaucoma
71
Describe phentolamine including the mechanism, effect, and what purpose it is used for
Non-selective, reversible alpha antagonist
**NOT used in HTN because it lowers BP too much and subsequently raises HR via baroreceptor reflex
72
Describe phenoxybenzamine including the mechanism, effect, and what purpose it is used for
Non-selective, IRreversible alpha antagonists
| No common uses
73
Describe prazosin including the mechanism, effect, and what purpose it is used for
Selective alpha 1 antagonist
| Treatment of HTN
74
What suffix is commonly used for alpha 1 selective antagonists
-osin
75
Describe tamsulosin including the mechanism, effect, and what purpose it is used for
Selective alpha 1 antagonist
| Treatment of benign prostatic hyperplasia
76
Describe yohimbine including the mechanism, effect, and what purpose it is used for
Selective alpha 2 antagonist
| Used in muscle building and enhanced sexual function
77
What suffix is commonly used for beta antagonists
-ol
78
Describe propanolol including the mechanism, effect, and what purpose it is used for
Non-selective beta-blocker
79
Describe metorpolol including the mechanism, effect, and what purpose it is used for
Beta 1 antagonist - prevent heart and kidney effects (contractility and BP) while maintaining B2 effects of vasodilation, K+ uptake
Especially useful in treating diabetics due to glycogenolysis effects of Beta 2 in liver and skeletal muscle
80
Describe pindolol including the mechanism, effect, and what purpose it is used for
Non-selective beta-blocker and partial agonist to intrinsic sympathetic activity
Treatment of HTN in runners where you would not want to further decrease HR
81
Describe carvedilol including the mechanism, effect, and what purpose it is used for
Combined alpha 1 and beta antagonist
| Treatment of chronic heart failure - prevents hypertrophy of the heart by blocking alpha 1
82
Describe Labetalol including the mechanism, effect, and what purpose it is used for
Combined alpha 1 and beta antagonist
| Treatment of HTN in pregnancy as well as hypertensive emergencies
