Exam 2 Material Flashcards
What enzyme metabolizes phenylephrine?
MAO
Monoamine oxidases
Which adrenergic agonist is NOT arrhythmogenic?
Phenylephrine
Which selective alpha 2 agonist is more highly protein bound?
Dexmedetomidine
Name the endogenous sympathomimetics
Norepinephrine
Epinephrine
Dopamine
Define chronotropy
Affects heart rate
What receptors does clonidine work on?
-alpha 1 and alpha 2 adrenergic receptors
-acts as an anti hypertensive
Why is clonidine use in PNB?
Extends life if PNB
What receptor does dexmetomidine work on?
Central acting alpha 2
What is dexmetomidine used for intra-operatively?
Sedative
Proanesthetic
Dexmetomidine blunts central ____ response
Sympathetic
What 5 things does dexmetomidine reduce in patient intraop
-opioid muscle rigidity
-reduces post op shivering
-little respiratory depression
-hemodynamically stabilizing effect
-reduced opioid requirements
Dexmetomidine can cause a _____ in HR
Decrease
Alpha 2 may lead to hypotension when combined with other anesthetics
What is a sympathomimetic
Stimulates adrenergic receptors
what is the protype drug for sympathomimetics
epinephrine
what receptor relates to vasculature
alpha 1
what receptor relates to heart rate
beta 1
what receptor relates to bronchiole smooth muscle
beta 2
what drug is an agonist for all adrenergic receptors?
epinephrine
what does alpha 1 stimulation do
-arteriolar vasoconstriction
-pulmonary artery vasoconstriction
What does beta 1 stimulation do
-increase HR
-increase myocardial contractility
-increased CO
what does beta 2 stimulation do
-vasodilation in airway smooth muscle
-vasodilation of skeletal muscle
-increase cAMP
what is mydriasis
contraction of iris= dilation
what are the metabolic effects of epi
hypokalemia
hyperglycemia
norepinephrine has ___ alpha 1 than epi
greater
norepinephrine has ___ B2
NO
when compared to epi, norepi has ___ effect on SVR, systolic/diastolic BP, and MAP.
This is due to its affect on the ___ receptor
greater
alpha 1
what is the first line vasopressor for septic shock
norepinephrine
how much metabolic effect does norepi have
limited (not as much K or blood sugar effect)
what systems does dopamine help regulate
-cardiac
-vascular
-endocrine
-central nervous system
-peripheral nervous system
what receptors does dopamine affect
D1 D2 alpha and beta
what are the effects of D1 stimulation
-vasodilation of renal, mesenteric, coronary and cerebral
what are effects of D2 stimulation
inhibits norepi release
what is the reward mechanism in the brain
dopamine
what receptors are activated at dopamine rate 0.5-3 mcg/kg/min? What is its effect?
D1 and D2
vasodilation, decreased arterial BP, increased renal and splanchnic blood flow
what receptors are activated at dopamine rate 3-10mcg/kg/min
B1
alpha 1 increase
what does an increase in dopamine dose put a patient at risk for
arrhythmias
what is the half life of dopamine
1-2 min
what 6 things does dopamine increase
-myocardial contractility
-renal blood flow
-GFR
-Na excretion
-Urine output
-intraocular pressure
what are two synthetic catecholamines
isoproterenol
dobutamine
what is isoproterenol used for
heart blocks
B1 B2 agonist
what are the effects of isoproterenol
-increased HR
-increased contractility
-decreased SVR through skeletal muscle vasodilation
what is dobutamine?
-synthetic catecholamine
-racemic mixture of isoproterenol
what receptor is dobutamine specific for?
B1, weak B2 effects
does dobutamine have alpha effects
yes at high doses
does isoproterenol have alpha effects?
NO
what is dobutamine used for?
heart failure
weaning from bypass
what are the effects of dobutamine?
increased contractility
decreased afterload
what are two synthetic noncatecholamines
ephedrine
phenylephrine
what is the indirect acting sympathomimetic
ephedrine- must go through metabolism
what receptor does ephedrine work on
alpha and beta
which synthetic noncatecholamine mimics epi
ephedrine
what is benefit of ephedrine over epi
less intensity
lasts longer
what happens when you keep giving ephedrine
tachyphylaxis, effect diminishes have to give higher doses
catecholamine depletion at the synapse
which synthetic noncatecholamine mimics norepi
phenylephrine
what receptor does phenylephrine act on
alpha 1
what kind of vessel does phenylephrine constrict
venous and arterial
what is a reflex effect of phenylephrine
baroreceptors reflex vagal from elevated BP, bradycardia
what is the effect of selective B2 adrenergic agonist
relax bronchioles and uterine smooth muscle
what is the protype drug for beta 2 agonist
albuterol
what are the routes of admin for B2 agonists
inhaled most common
oral and subq
what happens when you put inhaler through ETT
decrease dose by 50-70%
what is calcium used as in anesthesia
inotrope
when is ionized Ca used to treat cardiac depression
-volatile anesthetics
-citrate infused blood products
-post bypass
what has effect on heart: ionized Ca or total plasma calcium
ionized
acidosis ___ ionized Ca
increases
alkalosis ___ ionized Ca
decreases
infusion dose for isoproterenol
0.015-0.15mcg/kg/min
how is isoproterenol metabolized
rapidly by COMT
what is infusion dose of dobutamine?
2-20mcg/kg/min
IV dose of ephedrine
5-25mg
IM dose up to 50mg
ephedrine is a ___ inotrope and ____ O2 demand with CAD
positive, increase
what potent alpha agonist is the chemical precursor of epinephrine?
norepinephrine
an FDA Black Box warning is attached to what B2 selective agents?
salmeterol and formoterol
which adrenergic receptor agonist is metabolized by the liver?
ephedrine
which synthetic catecholamine is derived from dopamine?
isoproterenol
what is the precursor of norepinephrine
dopamine
How does labetalol possess intrinsic sympathomimetic activity (ISA)?
Partial stimulation (agonist) action at the beta adrenergic receptor while blocking endogenous catecholamines from binding to the beta receptor
Less potent than catecholamines and other beta agonists
Concerns with beta antagonists
-brandy arrhythmias
-obtunding the cardiovascular response to hypovolemia
-progressive heart block
-HF
-bronchoconstriction
Abrupt d/c can cause rebound HTN and tachycardia
What can happen to the selectivity of a selective beta blocker if dose increases
The degree of selectivity is diminished
What is the ratio of beta to alpha block for labetalol
7 (beta) : 1 (alpha)
What receptors does labetalol effect
Alpha 1
Beta 1 and beta 2
Non selective beta antagonist
Half life and metabolism of labetalol
Half life: 6 hrs
Metabolized in liver, eliminated by kidneys
Propranolol’s use as an anti-dysrhythmic is best related to its:
Membrane stabilizing ability (MSA)
Administration if a B2 receptor antagonist to a patient with COPD may trigger?
Bronchoconstriction
Which beta blocker has intrinsic sympathetic activity (ISA)
Labetalol
Which beta receptor antagonist undergoes renal metabolism
Atenolol
What’s the most common side effect of prazosin
Orthostatic hypotension
Which beta blocker is metabolized by non specific esterases?
Esmolol
What substance is a an agonist of acetylcholine
Nicotine
Nicotine is a cholinomimetic
What effect does diltiazem have on the AV node?
Negative dromotropic
Define dromotrope
-A dromotropic agent affects the conduction speed (the magnitude of delay) in the AV node of the heart
-influences the rate of electrical impulse propagation in the heart
Negative- prolongs AV node conduction
Positive- shortens AV node conduction
CCBs produce greater relaxation of ___ vs ____
Arterial than venous smooth muscle
Many CCBs induce coronary artery vasodilation and inhibit coronary artery vasospasm
Verapamil and diltiazem are class ____ antiarrhythmics that______
Class 4
That depress electrical impulses in the SA and AV nodes
Effects of CCBs on O2 supply and demand
Demand:
-decrease after load
-decrease preload
- decrease contractility
-can decrease or increase Hr
Supply:
- increases diastolic perfusion
-decreases vasoconstriction
-decreases arterial spasms
How do CCBs work?
Block the biochemical pores preventing the movement of ions across the membrane
Targets L form ca channels
What are CCBs used to treat
HTN
Arrhythmias
Peripheral vascular disease
Cerebral vasospam
Angina
Rank the CCBs (highest to lowest) ability to impair contractility
Verapamil
Nifedipine (Procardia)
Diltiazem
Nicardipine (Cardene)
Example: In a patient with decreased contractility you would choose Diltiazem over verapamil
Which CCB better control HR?
Verapamil and Diltiazem
Which CCB is the only one proven to reduce morbidity and mortality from cerebral vasospasm?
Nimodipine
CCBs preserve ____ while reducing ____
Preserve preload
Reduce LV after load
Which type of calcium channel do CCBs target
L type
Which CCBis often prescribed for Raynaud’s disease?
Nifedipine
What drug is a nitric oxide donor with great effect on venules than arterioles
Nitroglycerin
Which specific PDE inhibitors prevent platelet aggregation
PDE 3 inhibitors
Which specific receptor (subtype) mediates cardiovascular effects of vasopressin?
V1 receptor
Which PDE inhibitor is useful in inflammatory states?
PDE 4 inhibitors
Which PDE inhibitor selectively increases cGMP
PDE 5 inhibitors
The dry cough associated with an ACE-inhibitor is most likely due to
Accumulation of bradykinin
What are the best agents to augment the heart rate in a patient after heart transplant?
Epinephrine
Isoproterenol
what messenger does beta 1 stimulate
cAMP
what is an alpha 2 agonist
sympatholytic
what is the MOA of alpha 2 agonists
competitively bind to alpha 2 receptors inhibiting the neurotransmitter NE release
what can happen with ending of alpha 2 agonists
rebound HTN and tachycardia from increase in sympathetic flow
what are examples of alpha 2 agonists
clonidine and dexmetomidine (precedex)
where does dexmetomidine act
locus ceruleus
what are the benefits of dexmetomidine
blunts sympathetic response
airway reflexes remain unchanged
minimal resp depression
reduction of opioid requirements
use in awake intubations
what are side effects of dexmetomidine
bradycardia and hypotension
what can happen with large doses of dexemetodine
transient hypertension due to the crossover stimulation of alpha 1
what are withdrawal symptoms of dexmetomidine
HTN
tachycardia
anxiety
what is dosing for dexmetomidine
IV 0.1-1.5 mcg/kg/min
loading dose 1mcg/kg
where are alpha 2 receptors located
pre-synaptic neurons
what is the MOA of alpha antagonists
inhibit the effects of catecholamines and sympathomimetics on the heart and vasculature
what are effects of alpha antagonists
decreased BP
decreased BPH effects
what are side effects of non selective alpha antagonists
reflex tachycardia (baroreceptor mediated from vasodilation)
what medication do we use for pheochromocytoma
phenoxybenzamine (labetalol, prazosin)
what are examples of non selective alpha antagonists
phentolamine
phenoxybenzamine
what is the onset and half life of phenoxybenzamine
onset 1 hr
half life 24 hrs (due to covalent bond)
what happens with hypotensive patients and non selective alpha antagonists
vasodilation and more hypotension
what are examples of selective alpha 1 adrenergic antagonists
terazosin
prazosin
tamsulosin
what is the alpha 2 selective antagonist
yohimbine
used for some htn
what are uses of selective alpha antagonists
BPH and HTN
what does happens with beta 1 stimulation
increased contraction
increased HR
increased conduction rate through AV node
what are the effects of beta blockers
decreased HR
decreased AV conduction
decreased contractility
decreased myocardial oxygen consumption
relaxation of the heart
increased airway resistance
why are beta blockers used in CABG patients
decrease incidence of afib
what medication do you NOT use in asthma patients
non selective beta blockers (like propanolol)
what beta blocker is highly protein bound
propanolol
what are examples of selective beta blockers
metoprolol
atenolol
esmolol
what receptors are selective beta blockers selective for
beta 1
what kind of beta blockers are better with airway diseases or asthma
cardioselective
what is the risk of non selective beta blockers
more side effects
risk of bronchospasm
should patients stop beta blockers in periop period
no, continue to avoid rebound effect
what kind of beta blocker is best for diabetic patients
atenolol
what are anesthesia considerations for Beta antagonists
myocardial depression
airway resistance
changes in metabolism
increased extracellular potassium
anesthesia interactions
nervous system effects
fetal bradycardia
hypotension
what are the side effects of beta blockers
MYOCARDIAL DEPRESSION
bradycardia
hypotension
cardiogenic shock
how do you treat beta antagonist overdose
glucagon and maybe calcium chloride
what are the side effects of beta blockers
airway resistance (more likely with propanolol)
masks symptoms of hypoglycemia (tachy, palpitations, tremors anxiety)
increased extracellular K (nonselective)
what kind of beta blockers are not recommended in diabetic patients
non selective (propanolol)
how does propanolol effect local anesthetics
slows clearance of local amides
decreases pulmonary uptake of fentanyl (2-4x in circulation)
how does timolol interact with inhaled anesthetics
profound bradycardia
what beta blocker can cross the BBB and what are the effects
propanolol (lipid soluble)
causes lethargy and fatigue
what beta blockers can cross the placenta and what is the effect
propanolol and labetalol- cause hypotension and bradycardia
still the first line therapy for acute onset or emergent HTN in pregnancy
what receptors does labetalol work on
alpha 1 and non selective beta antagonist
what is the MOA of labetalol
alpha 1 blockade: lowers systemic BP by decreasing SVR
beta nonselective blockade: lowers reflex tachycardia by vasodilation
what are the clinical uses of labetalol
HTN emergencies
rebound HTN
pheochromocytoma
what are common side effects of labetalol
orthostatic hypotension
bronchospasm
CHF
bradycardia
heart block
what are uses of CCBs
HTN
cardiac arrhythmias
angina pectoris
what are the pharmacological effects of CCBs
decreases HR
decreases myocardial contractility
decreases SA node activity
decreases cardiac conduction through the AV node
decreases systemic BP
relaxes smooth muscle
vasodilation
what are two types of CCBs
dihydropyradines
non-dihydropyradines
what do dihydropyradines effect
vessels
what are examples of dihydropyradines
nifedipine
nicardipine
amlodapine
nimodipine
what do non dihydropyridines effect
heart
what are the divisions of non dihydropyridine CCBs
phenylalkylamines (verapamil)
benzothiazepines (diltiazem)
what vessels does nimodipine mostly work on
cerebral vessels
think arterial vasospasm
what vessels do nifedipine and nicardipine work on
arteriolar beds
what is the effect of nifedipine
coronary/peripheral arterial vasodilator
no effect on SA/AV
increases in HR from baroreceptors
angina pectoris
what are side effects of nifedipine
flushing, vertigo, head ache
may have: peripheral edema, hypotension, paresthesias, skeletal muscle weakness
what happens when you abruptly d/c nifedipine
coronary artery vasospasm
where does nimodipine work?
cerebral arteries
highly lipid soluble
what are uses for nimodipine
cerebral vasospams
cerebral protection after MI
what is contraindication for any BB or CCB
heart block
what does verapamil do
negative chronotropy on SA
depresses AV
negative inotrope
cardiac muscle vasodilates coronary arteries
what does verapamil treat
SVT
angina pectoris
essential HTN
hypertrophic cardiomyopathy
what are side effects of verapamil
HF
bradycardia
SA dysfunction
AV block
ventricular dysrhythmias
WPW syndrome
what does diltiazam do
blocks ca channels and Na-K pump
inhibits calcium calmodulin binding
what does diltiazem treat
SVT and HTN
what is a contraindication for CCBs
heart blocks
conduction abnormalities
can you continue CCBs through surgery
yes
how can you reverse CCB overdose
IV calcium or dopamine
how do CCBs affect NMB
increase effects
how do CCBs effect K levels
hyperkalemia
especially with K and verapamil
how do CCBs effect platelet function
Interfere with platelet functions
how do CCBs effect digoxin
increases the plasma concentration
how do CCBs effect H2 antagonists
cimetidine and ranitidine increase CCB plasma concentrations
name some other outcomes from CCBs
prevent ischemic reperfusion injury
decreased effect of nephrotoxic drugs/contrast media
increases renal blood flow and GFR
what is stage 1 HTN
130/80-139/89
what is stage 2 HTN
> =140 sys and >= 90 dias
what is the most common type of HTN
primary/essential HTN
what are causes of secondary HTN
OSA
renal disease
renal artery stenosis
pheochromocytomac
cushings
hyper/hypo thyroid
oral contraceptives
chronis NSAID use
antidepressants
ETOH
aortic coarctacion
what are risks of HTN
atherosclerosis
HF
stroke
renal disease
death
what are lifestyle changes for HTN
change diet
smoking cessation
weight loss
exercise
lower salt intake
medication
what is initial therapy for essential htn
thiazide diuretics then dihydropyridine CCB, ace or arb
should antihypertensive therapy be continued through surgery
YES
what are the adrenergic receptors
alpha 1 alpha 2 beta 1 beta 2
alpha 1 stimulation causes
vasoconstriction
increase in peripheral resistance
increase in BP
mydriasis
increase closure of bladder sphincters
NE>EPI
alpha 2 stimulation causes
inhibits norepi release
inhibits Ach release
inhibits insulin release
EPI>NE
beta 1 stimulation causes
increased HR
increased lipolysis
increased myocardial contractility
increased renin
EPI= NE
beta 2 stimulation causes
vasodilation
decreased peripheral resistance
bronchodilation
increased glycogenolysis (muscle and liver)
increased glucagon release
relaxes uterine smooth muscle
EPI» NE
what are examples of nonselective BB
propanolol, carvedilol, labetalol
what is MOA of metoprolol
B1 blocker
what is MOA of labetalol
A1 B1 and B2 blocker
what is MOA of esmolol
B1 blocker
what is class of CCB is nicardipine
dihydropyridine CCB
what is mechanism of hydralazine
arteriolar dilator
what is mechanism of nitroprusside
NO donor
what is mechanism of nitroglycerin
NO donor
what receptor do selective BB attach to
B1
what is MOA of alpha 1 antagonists
lower BP by blocking alpha 1 receptors so they cant constrict
dilate venous and arterial vessels
what is the protype drug for alpha 1 blockers
prazosin
what are side effects of alpha 1 antagonists
vertigo
fluid retention
orthostatic hypotension
what type of drugs interfere with prazosin anti HTN effects
NSAIDS
if a pt is on alpha 1 antagonist what alpha agonist would you use?
epi
what anesthesia procedure can cause hypotension when pt is on alpha 1 antagonist
spinal/epidural
what receptor does clonidine work on
alpha 2 agonist
what are desired effects of clonidine
vasodilation
decreased BP
decreased HR
decreased CO
what are side effects of clonidine
sedation
dry mouth
skin rashes
impotence
orthostatic hypotension
how do you stop clonidine use
gradually decrease over 7 days
what can happen with abrupt d/c of alpha 2 antagonist
rebound HTN
advantage of using clonidine and dexmetomidine together
induced sedation
decreased anesthetic requirements
improved perioperative hemodynamics
what is the MOA ace inhibitors
decreased angiotensin 2 production leading to decreased vasoconstriction
how does angiotensin 2 produce vasoconstriction
leads to increased release of Ca from sarcoplastic reticulum to produce vasoconstriction
what is MOA of ARBs
block binding of angiotensin 2 to AT1 receptor blocking angiotensin 2 from causing vasoconstriction