Week 6 Vasoactive drugs Flashcards
1
Q
Autonomic nervous system is made of:
A
Sympathetic and Parasympathetic
2
Q
Sympathetic preganglionic fibers are _____ and postganglionic fibers are _____
A
Short, Long
Inervated organs/target tissue are far away whereas ganglion are located directly beside the spinal cord
3
Q
What is the goal of the autonomic nervous system?
A
Maintain homeostasis
4
Q
Parasympathetic preganglionic fibers are _____ and postganglionic fibers are _____
A
Long, Short
5
Q
What is the origin of SNS preganglionic neurons?
A
Thoracic & Lumbar; T1-L2
6
Q
What is the origin of PNS preganglionic neurons?
A
Cervical & Scaral
7
Q
What is the presynaptic neurotransmitter for SNS?
A
Acetylcholine
8
Q
What do preganglionic fibers interact with in the Adrenal glands?
A
Chromaffin cells
9
Q
What is the neurotransmitter for postganglionic synapses in the SNS?
A
Norepinephrine
10
Q
What is the one exception to the postganglionic neurotransmitter in the SNS?
A
Sweat glands; Acetycholine
11
Q
Chromaffin cells release:
A
80% Epinephrine, 20% Norepinephrine (reversed w/ pheochromocytoma)
12
Q
When Epinephrine and Norepinephrine are secreted from the Adrenal Medulla, they are then considered
A
Hormones
13
Q
What three substances are synthesized in nerve terminals or adrenal medulla?
A
Epinephrine, norepinephrine, and dopamine
14
Q
What are the effects of cortisol being secreted from the adrenal cortex?
A
enhances norepinephrine conversion to epinephrine
15
Q
What nerve is the major regulator of the parasympathetic nervous system?
A
Vagus (CNX)
16
Q
What neurotransmitter is secreted at the postganglionic synapse of the PNS?
A
Acetylcholine
17
Q
What are the 5 functions of the vagus nerve?
A
- Slow HR (negative chronotropic)
- Slow Conduction (negative dromotropic)
- Salivate
- Miosis
- Empties (bladder/rectum)
18
Q
What 2 Na channel blockers lengthens AP?
A
procanimide
flecinide
19
Q
What NA. channel blocker shortens AP?
A
Lidocaine
20
Q
T/F Lidocaine is used for long term treatment of arrythmias
A
FALSE- poor oral bioavalibility
21
Q
How do Class 1 antiarrythmic medications work? (lidocaine, procanimide, flecainide)
A
lengthens AP and Phase 0 depolarization to decrease conduction speed
22
Q
What antiarrythmic increases pacemaker capture threshold?
A
Flecainide
23
Q
What is the beta blocker of choice to treat tachycardia perioperatively?
A
esmolol OR labetalol for tachycardia & HYPERTENSION
24
Q
What antiarrythmic class is Amiodarone in?
A
Class III
25
What neurotransmitter is released from ALL preganglionic auntonomic fibers?
Acetylcholine
26
What neurotransmitters are released in the ANS and PNS postganglionic fibers?
ANS: Norepinephrine OR Dopamine
PNS: Acetylcholine
27
_____ activates alpha1 which results in an ______ in blood pressure which causes ______ due to barorecptor response
Phenylephrine, increase, reflex bradycardia
28
What receptors does epinephrine work on?
Small alpha
Some beta 1 and 2
29
What receptors does norepinephrine work on?
Large alpha
some beta 1
30
What receptors does dopamine work on?
Some alpha1 and beta1, small beta2, large dopamine receptor
31
What receptors does isoproterenol work on?
Large beta1 and beta2
32
What receptors does dobutamine work on?
Large beta1 small beta2
33
What are the NATURAL catecholamines?
Epinephrine
Norepinephrine
Dopamine
34
What are the synthetic catecholamines?
Isoproterenol
Dobutamine
35
What are the synthetic noncatecholamines?
Ephedrine
Phenylephrine
36
What receptor does ephedrine act on?
some alpha1, small beta1 and 2
37
What receptor does phenylephrine work on?
Large alpha1
38
What sympathomimetic has both direct AND indirect effects?
Ephedrine
39
What are the effects of alpha 1 receptor stimulation?
vascular smooth muscle constriction (increased SVR), pupil dilation
40
What are the effects of alpha 2 receptor stimulation?
sedation, bradycardia, vasodialation
41
What are the effects of beta 1 receptor stimulation?
Positive chronotropic and inotropic effects
increased renin and angiotensin and cAMP
42
What are the effects of beta 2 receptor stimulation?
bronchodialation, vasodialation, tocolytic
43
What are the effects of dopamine receptor stimulation?
Increase CO and renal/mesenteric blood flow
D2: inhibits norepi release
44
What are the three mechanisms that remove neurotransmitters from the synaptic cleft?
1. Uptake into presynaptic terminals
2. Extraneural uptake
3. Diffusion
45
What is a sympathomimetic?
Drug that produces same effects as catecholamines
46
What two enzymes metabolize norepinephrine?
COMT and MAO
47
What are the effects of beta 3?
lipolysis, thermogenesis in brown fat, bladder relaxation
48
What are the steps to catecholamine synthesis?
Tyrosine-> Dopa -> Dopamine -> Norepinephrine -> Epinephrine
49
Synthetic non-catecholamines are metabolized by
MAO
50
What cardiac phase does epinephrine effect?
Increases spontaneous phase 4 depolarization
51
What is the dose of Epinephrine push to support blood pressure?
2-8mcg
52
What are the lab changes caused by epinephrine?
Hypokalemia and hyperglycemia
53
Can epinephrine cross the BBB into the brain/CNS?
No, it is poorly lipid soluble
54
Why is epinephrine added to local anesthetics?
1. decreased bleeding
2. vasoconstriction to decrease absorption- thus longer effects
3. less absorption leading to cardiotoxicity
55
What is the effect of epinephrine on diastolic blood pressure?
decreases it, widening the pulse pressure
56
What is the issue with giving too high of a dose of epinephrine? (10-20mcg)
the alpha stimulation causes an increase in afterload that may impede increases in CO
57
What is racemic epinephrine for?
stabilizes mast cells for severe croup (subglottic edema) and postextubation. diluted and nebulized *must be observed for 2H rebound swelling*
58
what is the dose for anaphylaxis Epi?
0.5-1.5mg
59
What should be done with 1:1,000 epi?
Dilute or IM for anaphylaxis
60
How much epi should be given at a time during a code?
1mg of 1:10,000
61
What is the concentration of "baby epi"?
1:100,000
62
What two drugs interact with epinephrine?
Halothane: arrythmias
Cocaine: block reuptake
nonselective beta blockers: alpha 1 exaggerated response
63
What are the effects of norepinephrine?
increased HR, conduction, contractility, SVR
64
What are 2 cautions in using norepinephrine?
increases O2 consumption and causes metabolic acidosis
65
What neurotransmitter is secreted from postganglionic sympathetic nerve endings?
norepinephrine
66
Why does norepinephrine effect drug metabolism?
by decreasing hepatic blood flow
67
Norepinephine should be used with caution in what patient population?
right sided heart failure due to increased preload
68
How do you treat pressor extravasation?
phentolamine 5-10mg in 10mL NS
69
What occurs with administration of dopamine at 0.5-3mcg/kg/min?
d1 and d2 vasodialation
70
What occurs with administration of dopamine at 3-10mcg/kg/min?
Beta1 and Alpha1 increases
71
What is the half life of Dopamine?
1-2 minutes
72
What individuals should use caution with dopamine?
individuals with increased intraocular pressure (increases it even more)
73
T/F the precursor to dopamine, L-dopa can cross the BBB but dopamine cannot.
TRUE
74
Dopamine has direct and indirect effects that:
Direct: vasoconstriction, inotropey
Indirect: inotrope that depends on norepinephrine for actions
75
How is dopamine metabalized?
MAO and COMT
76
What is the concern with high dose (10-20mcg/kg/min) dopamine?
vasoconstriction combats the renal perfusion effects
77
What are Dopamines effects on glucose?
can inhibit insulin which can cause hyperglycemia
78
Why is dopamine good for post cardiopulmonary bypass patients?
increases CO, dialates vascular beds, decreases SVR -> mimics balloon pump
79
What is the most potent beta sympathomimetic?
isoproterenol
80
how is isoproterenol metabolized?
COMT
81
What is the dose of isoproterenol and what is it best at treating?
1-5mcg/min Heart block
82
What is dobutamine good for?
Heart failure, weaning from bypass
83
Why do we no longer use isoproterenol for inotropic effects?
dobutamine and milranone are better
84
When using isoproterenol, the net increase in cardiac output is due to:
Increased systolic blood pressure
85
Why does isoproterenol cause a DECREASED map?
high risk for arrythmias
decreased coronary blood flow
increase myocardial O2 requirements
86
Is dobutamine selective or nonselective?
Selective Beta1
87
What is the dosage for dobutamine?
2-10mcg/kg/min
88
What medications must be dissolved in D5W and why?
Dopamine and Dobutamine- to avoid inactivation of the catecholamine in an alkaline solution
89
dobutamine infusion greater than 3 days can cause:
Down regulation which can cause the need to increase dosage
90
What effects does dobutamine have on the coronary arteries?
vasodialates
91
What are the effects of ephedrine?
direct: binds to alpha and beta receptors
indirect: inhibits neuronal norepinephrine reuptake and displaces more norepinephrine from storage vesicles
DOSE: 5-15mg
92
What is the dose for ephedrine?
5-15mg
93
How does phenylephrine work and what is the dosage?
alpha1 receptors, primarily venoconstriction 50-200mcg bolus
94
What is a common concern with phenylephrine?
reflex bradycardia due to baroreceptor response to increase in SVR
95
What is a less common effect of ephedrine?
anti-emetic, 0.5mg/kg IM
96
Why is the second dose of ephedrine less responsive than the first?
tachyphylaxis
97
What causes ephedrine tachyphylaxis?
1. depletion of norepinephrine stores
2. persistent block of receptors
3. occupied receptor sites
98
What is the most common ephedrine supplied dose? dilution?
50mg/mL
dilute into 5mL NS to achieve 10mg/mL concentration
give 0.5mL at a time to give 5mg
99
What is the most common phenylephrine supplied dose? dilution?
10mg/mL
1. 0.1mL drug in 9.9mL NS = neo stick 100mcg/mL
2. 10mg in 100mL bag = 100mcg/mL
3. 20mg in 250mL bag = 80mcg/mL
4. 10mg in 250ml bag = 40mcg/mL
100
Does phenylephrine cause arterial or venous constriction?
Venous
101
How many mcg at a time should be given to support blood pressure?
50-200mcg
102
What is the dosage for a continuous infusion of phenylephrine?
20-50mcg/min
103
What receptor does dexmedetomidine work on?
Alpha2
104
While an alpha agonist causes reflex bradycardia, an alpha antagonist causes
reflex tachycardia
105
What is the dosage of a vasopressin infusion?
0.04-0.1unit/min
106
What is the infusion rates for norepinephrine, epinephrine, and dobutamine? (Hint: they're all the same)
1-20mcg/min
107
What is the milrinone infusion dosage?
0.375-0.75mcg/min
with or without bolus of 37.5-75mcg/kg
108
What class of antiarrythmics greatly decreases Phase 0 depolarization?
Class IC
Slightly in Class IA
(blocks NA channels)
109
What occurs in phase 0 of the cardiac cycle?
NA channels lead to depolarization of the cell
110
How do class III antiarrythmics effect refractory period?
greatly increased
111
How do class III antiarrythmics effect action potential?
greatly increased
112
What is an example of a cardiac glycoside?
digoxin
113
What are indications for digoxin?
SVT, PAT, Afib, Aflutter, CHF
114
How does digoxin work?
slows conduction of impulses through AV node
positive inotrope
115
Why is digoxin not a first choice drug?
increases risks of sudden cardiac death from cardiac dysrhythmias
116
What is a major concern with digoxin?
Narrow theraputic range; Toxicity
117
What are the direct and indirect effects of digoxin?
direct: modify electrical and mechanical activity
indirect: evoked by reflex alteration in ANS activity
118
What ratio of individuals experiencing toxic levels of digoxin show symptoms?
1:5
119
What is the therapeutic digoxin level?
0.5-2.5ng/mL
120
What are early signs of digoxin toxicity?
anorexia, n/v
121
What ekg changes are associated with digoxin toxicity?
atrial or ventricular dysrhythmias, incomplete to complete heart block
122
How do we treat digoxin toxicity?
correct cause
treat dysrhythmia
pacer if needed
potassium replacement if needed
123
what drugs can cause digoxin toxicity and why?
diuretics from hypokalemia
124
What anesthetic drug effects cardiac glycoside levels?
succinylcholine
125
What sympathomimetics could cause an increased risk of dysrythmias in individuals taking cardiac glycosides?
Beta agonists
126
what can occur when giving IV calcium to an individual on cardiac glycosides?
dysrythmias
127
What is the interaction between antacids and digoxin?
decreased GI absorption = subtheraputic levels
128
What is the MOA of Phosphodiasterase inhibitors?
decreases hydrolysis of cAMP and cGMP to increase intracellular concentrations of CA in myocardium and vascular smooth muscle-> increasing intracellular calcium levels and contractility -> uptake of calcium causes smooth muscle relaxation/ decreased SVR
129
Amrinone is also know as:
Inamrinone
130
Why is amrinone no longer used?
milrinone is more potent with less side effects
131
What is a useful purpose of milrinone in arteriografts?
reverse vasospasm
132
What causes milrinones long half life?
highly protein bound
133
Which drug decreases cardiac filling pressures more: dobutamine or milrinone?
milrinone
134
what are side effects of milrinone?
decreased SVR and venous return could cause hypotension
potentially proarrythmic in CHF
135
Where in the body is calcium used?
1. neuromuscular junction
2. skeletal muscle contraction
3. cardiac muscle contraction
4. blood coagulation
5. exocytosis of neurotransmitters
6. bone component
136
What is the effect of calcium on the heart?
positive inotrope
137
What is the calcium dosage of inotropic purposes?
1000-3000mg
138
The active form of calcium is:
ionized
139
acidosis ______ calcium levels, whereas alkalosis ______ calcium levels
increases, decreases
140
What is the most common type of hypertension?
primary/essential
141
When should antihypertensive medications be stopped before surgery? why?
continue until surgery
rebound hypertension can occur with abrupt cessation
142
Metoprolol MOA, dose, onset, and half-life:
selective Beta1 blocker/antagonist
1-5mg IVP
1-5mins
3-7hrs
143
Labetalol l MOA, dose, onset, and half-life:
nonselective alpha1, beta1and2 antagonist
5-20mg IVP
1-5min
6hrs
144
Esmolol MOA, dose, onset, and half-life:
selective beta1 blocker/antagonist
500-1000mcg/kg
1-2min
9mins (metab plasma esterases)
145
Nicardipine MOA, dose, onset, and half-life:
Dihydropyridine CCB
100-400mcg
2-10mins
2-4hrs
146
Hydralazine MOA, dose, onset, and half-life:
arteriolar dialator
5-20mg
5-20min
2-8hr
147
Nitroprusside MOA, dose, onset, and half-life:
NO donor
infusion only 0.25-4mcg/kg
1-2min
<10mins
148
Nitroglycerin MOA, dose, onset, and half-life:
NO donor
20-400mcg
1-2min
1-3min
149
When administering a beta2 agonist, an ETT decreases MDI dose by what percentage?
50-70%
150
What is the purpose for selective beta blockers and some examples?
low-mod doses are unlikely to cause bronchospasm and mask hypoglycemia
acebutolol, atenolol, metoprolol, bisoprolol
151
What is a major concern of using beta blockers?
mask signs of hypoglycemia -> increases risks of coma
152
What are some examples of nonselective beta blockers?
propranolol, carvedilol, labetalol
153
What are some side effects of beta blocker use?
bradycardia
heart block
CHF, claudication
bronchospasm
sedation, impotence
angina/MI
154
What population should nonselective beta blockers be avoided in?
lung patients (asthma, COPD)
selective beta blockers are safe for them
155
What is an example of a Alpha1 blocker? What are the effects and side effects?
Prazosin
decreases SVR via vasodialation, decreases preload and CO
SE: vertigo, fluid retention, orthostatic hypotension
156
What are the two most common Alpha2 blockers?
dexmedetomidine
clonidine
157
Why does dexmedetomidine cause CNS effects while clonidine acts primarily on blood pressure management?
the subtype receptors dex acts on are primarily found in the CNS whereas the ones clonidine work on are in vascular smooth muscle
158
What are some side effects of Alpha2 agonists?
bradycardia, sedation, decreased pain perception, rash, impotence, ortho hypotension
159
What is the most common side effect of an ACE inhibitor?
Cough
minor: URI symptoms
160
What is the most DANGEROUS side effect of an ACE inhibitor?
Angioedema- upper airway blockage = emergency
161
What is the MOA of an ACE inhibitor?
ACE is the enzyme that converts ang I to ang II, this reaction occurs in the lungs. ACE inhibitors prevent ang I from becoming the more potent ang II
162
What is the MOA of ARBS?
blocks the vasoconstricting effects of angiotension II without affecting ACE activity
163
When should ACEs and ARBs be d/c'ed prior to surgery?
12-24 hours prior
164
What drug might be useful intraoperatively for a patient who routinely takes ACE/ARBs?
vasopressin (assist in the alpha reaction to sympathomimetics)
165
How do dihyrdopyridine CCBs work?
bind to calcium channels on vascular smooth muscle, promoting vasodilation NICARDIPINE
166
How do NON dihydropyridine CCBs work?
block calcium channels in heart muscle, reduce Ca in cardiac cells, leading to a decrease in the heart rate and contractions DILTIAZEM
167
What type of calcium channel blockers have more effect on blood vessles?
dihydropyridines
168
What type of calcium channel blockers have more effect on the heart?
non-dihydropyridines
169
what are the two non dihydropyridines?
Verapamil
diltiazem
170
what are some examples of dihydropyridines?
nifedipine, amlodipine, nicardipine, clevidipine
171
What are the three conditions dihydropyridines treat?
1. hypertension
2. prinzmetal angina
3. raynaud's syndrome
172
What are side effects associated with dihydropyridine use?
reflex tachycardia, negative inotropy, hypoxemia d/t worsening VQ mismatch (shunting)
173
do nondihydropyridine CCBs also have vasodilatory effects?
yes
174
What does inhibition of PDE3 cause?
positive inotropy
175
what does inhibition of PDE cause?
vascular smooth muscle relaxation
176
What do PDE5 inhibitors treat?
Erectile dysfunction and pulmonary hypertension
177
What do PDE3 treat?
myocardial infarction, intermittent claudication, heart failure
178
What are side effects of PDE5s?
headache, flushing, dyspnea
179
What are side effects of PDE3s?
Ventricular dysrhythmias, headache, hypotension
180
What does inhaled nitric oxide do?
relaxes pulmonary arterial vasculature & improves ventilation-perfusion matching
181
Is inhaled nitric approved for the adult population?
NO
182
What is the "Off label" use of nitric oxide in adults to treat?
severe pHTN in the setting of right heart dysfunction/failure in heart/lung transplants
183
What would occur if inhaled nitric oxide was stopped abruptly?
rebound pulmonary hypertension
184
What is the indication for nitrates?
suspected MI, volume overload w/ HF, hypertension
185
Do nitrates primarily dilate veins or arteries?
veins AND coronary arteries
186
Whats the MOA of nitrates and SNP?
generates NO stimulates production of cGMP to cause peripheral vasodialation
187
What's the rate of a nitroglycerin gtt?
5-600mcg/min
188
How does SNP work?
interacts with oxyhemoglobin leading to an increase of cGMP to inhibit Ca entry into cell and thus vascular smooth muscle relaxation
189
What is a major concern associated with a nitroprusside drip and when does it become a valid concern?
Cyanide toxicity
+3 days of administration
>2mcg/kg/min
190
Nitroprusside side effects:
inhibits platelet aggregation
VQ mismatch/shunting/decreased PaO2
increases ICP
tachy/decreased BP/+inotropy
Coronary steal
decreased renal function
191
Nitroprusside should be used with caution in what patient population?
neuro peeps/ increases ICP
192
What is coronary steal and what medication causes it?
vasodilation of a myocardial segment's vasculature is associated with “steal” of blood from another myocardial segment
nitroprusside
193
How is cyanide toxicity treated?
d/c SNP
100%O2
sodium bicarb
sodium thiosulfate (150mg/kg)+/ hydroxycobalamin (5mg/kg)
194
What are the three things caused by cyanide toxicity?
1. Anoxic tissue ischemia
2. anaerobic metabolism
3. Lactic acidosis
195
What is methemoglobinemia?
an adverse effect of SNP, uncommon
dose to cause exceeds 10mg/kg
196
What vessels does hydralazine work on?
arteries
197
What are two major concerns when administering hydralazine?
reflex bradycardia
coronary steal
198
What patient population should not receive hydralazine?
patients experiencing MI or CAD
199
What is the sympatholytic of choice for pregnant women?
hydralazine
200
How does hydralazine affect SVR?
Decreases it
201
What can occur with long term use of hydralazine?
systemic autoimmune syndrome
202
What is the dose for hydralazine?
2.5-5mg/5min 20mg max
203
What is a common nitrate used to prevent angina and to decrease SVR in HF?
Isosorbide dinitrate
204
How does isosorbide dinitrate work?
similarly to Nitro
205
What is a side effect of isosorbide?
orthostatic hypotension
206
Isosorbide dosage:
60-120mg
207
Why would an MAOI create issues with blood pressure management?
MAOIs alter the break down of catacholimines
208
What amino acid is the"building block" of catacolimines?
tyrosine
209
What are the two ways neurotransmitters can be metabolized?
1. reuptake
2. metabolized by MAO into homovinellic acid
210
When in the operative period is hypotension most common?
during induction
211
What is the blood pressure goal during surgery?
Maintain within 20% of baseline with a map of >65
212
What occurs if we do not maintain our blood pressure goals perioperatively?
MI
AKI
Stroke
Delirium
213
When should a beta blocker be D/C'ed prior to surgery?
maintained until day of surgery
214
When should a CCB be D/C'ed prior to surgery?
maintained until day of surgery
215
What blood pressure necessitates postponing procedure?
SBP >180 or DBP >110
216
What is the onset time for ephedrine?
2-5min
217
Why isnt ephedrine used as a drip?
Tachyphylaxis
218
What is the push dose of ephedrine?
5-15mg/ 1-2 doses over 5-10minutes
219
What non-catacholamine sympathomimetic is resistant to COMP and MAO?
Ephedrine
220
What happens if patients taking MAOIs receive ephedrine?
exaggerated hypertensive effect
221
What is the push dose for phenylephrine?
80-100mcg
222
What is the onset for phenylephrine?
less than a minute
223
If a patient is bradycardic and hypotensive, what is the first line medication?
ephedrine
224
If a patient is nsr-tachy and hypotensive what is the first line medication?
phenylephrine
225
What is the ratio of baby epi?
1:100,000
226
What is the normal push dose of baby epi?
2-8mcg every 1-5mins
227
What is the normal push dose of norepinephrine?
3-12mcg/1-2mins
228
Why are we less likely to give a push dose of norepinephrine?
higher risk of a lethal dose
229
What is the push dose for vasopressin?
0.5-1unit
230
What is the indication to give a push of vasopression?
hypotension in pt's taking ACE
sepsis
shock
bypass
catecholamine resistance
231
What medication can be given if vasopressin does not help hypotension?
methylene blue 1-3mg/kg
232
What is the MOA of methylene blue?
interferes with NO/inhibits vasorelaxants
233
Pronation and hypotension can cause what adverse event?
blindness
234
What is our first line treatment for hypertension perioperatively?
increase volatile gas- probably due to ANS/gases cause vasodialation
235
What physiological process causes thereputic hypertension to occur?
stroke
236
In what setting could hydralazine cause significant hypotension?
in the presence of nitrates or acute ETOH intoxication
237
What is the preferred antihypertensive agent for ischemia?
nitroglycerine
238
What are the two choice drugs for severe acute hypertension?
nitroglycerine and sodium nitroprusside
239
What are the the two choice drugs for hypertension in the setting of tachycardia?
Esmolol and labetolol
240
What is the first choice drug for primary/essential hypertension?
thiazide diuretic
241
What two drug classes are used to manage bradycardia?
anticholinergics: atropine/glyco
catecholamines: epi/ephedrine/isoproterenol
242
While undergoing cardiopulmonary bypass the ______ artery is a more accurate measurement than the radial.
Brachial
243
What is Pulsus Paradoxus?
decreases in systolic blood pressure during inspiration
244
What has higher levels of proteins, plasma or interstitial fluid?
plasma
245
What is Cushing's triad?
hypertension
bradycardia
irregular respirations
246
Cardiac output =
Stroke volume x Heart rate
247
What is the determining factor of stroke volume?
venous return/preload
248
What are anesthetic agents effects on cardiac output?
decreased
249
Why should norepinephrine be used with caution in patients with right sided heart failure?
increase in preload can more advanced failure
250
High dose dopamine can cause:
reflex bradycardia
251
T/F dobutamine is a racemic mixture
True
252
What plant are cardiac glycosides derived from?
foxglove
253
What could occur with digoxin toxicity and direct current cardioversion?
Ventricular fibrillation
254
A Frank-Sterling Curve shift to the left indicates:
increased inotropy/CO
255
What are the effects of digoxin on EKG?
prolonged PR
shortened QTc
ST depression
small T wave
256
T/F ekg changes related to digoxin go away once drug is cleared
False, EKG changes remain weeks after drug discontinuation
257
What is a lusitropic state?
relaxation (difficult in diastolic heart failure)
258
What causes milrinone to have such a long half life?
highly protein bound
259
What does clonidine treat?
HTN, tremors from CNS stimulants, opioid withdrawls
260
What is the dosage for dexmetatomidine?
0.1-1.5mcg/kg/min
261
T/F dexmedetomidine can be stopped abruptly with no issues regardless of dose.
False, withdraw symptoms occur when at high dose for multiple days
262
What is the push dose for dexmedetomidine?
0.25-1mcg/kg
263
T/F If a patient is taking propranolol, this affects the metabolism of other drugs such as local anesthetics and fentanyl
True
264
Whats the difference between metoprolol tartrate and succinate?
tartrate 1/2 life: 2-3hrs
succinate 1/2 life: 5-7hrs
265
How is esmolol metabolized?
plasma esterases
266
What is the push dose of esmolol?
0.5mg/kg
267
What are indications for esmolol?
electroconvulsion therapy, phenochromocytoma excision, thyrotoxicsis, pregnancy, epi/cocaine cardio toxicity
268
What would occur with absorption of cocaine or epinephrine to an individual taking a beta1 antagonist?
pulmonary edema, cardiovascular collapse
269
Why is esmolol a painful injection?
It's acidic
270
What are contraindications for an esmolol push?
AV block, acute cardiac failure
271
What is the heart rate goal when giving a beta blocker?
65-80
272
What part of the cardiac cycle do Beta blockers work in?
decrease rate of phase 4 spontaneous depolarization
273
How should excessive beta blockade be treated?
7mcg/kg atropine, 2-25mg isoproterenol
glucagon, ca cl, pacer
274
What two medications should NEVER be given to a patient with excessive Beta blockade?
Epinephrine and dopamine
275
What cardiac arrythmia does propranolol treat?
torsades
276
What are the two mixed alpha and beta blockers?
Labatolol and caredilol
277
What is the ratio of alpha to beta selectivity for labatolol?
1:7
278
What are the two subtypes of CCBs?
Dihydropyridines and
nondihydropyridines:
phenylalkylamines (verap) and benzothiazapines (Dilt)
279
How do nondihydropyridines work?
bind to calcium channel to maintain inactive state
280
What is one thing all CCB's treat?
coronary artery vasospasm
281
which nondihydropyridine is a racemic mixture?
verapamil
282
Verapamil MOA:
racemic mixture: dextro: slows NA channels, levo: slows calcium channels- decreasing AV conduction
283
Why cant verapamil be given to a patient with WPWS?
could cause ventricular arrythmias
284
What are the three indications for verapamil?
1. SVT
2. Angina
3. Hypertension
285
What CCB works best on cerebral vessels?
nimodipine
286
What can occur with abrupt cessation of CCBs?
coronary vasospasm
287
What CCB has the most profound vasodilatory effects?
nicardapine
288
Which CCB comes in a lipid solution?
clevidipine
289
Which CCB should not be given to patients with hyperlipidemia or pancrentitis?
clevidipine
290
How do we treat a diltiazem overdose?
dopamine and calcium
291
What can occur when administering volatile gases to patients on CCB's?
prolonged PR interval
292
What are some nonpharmalogical methods to decrease blood pressure?
low sodium diet, weight loss, exercise, fluid restriction
293
Why arent beta blockers first line for essential hypertension management?
adherance/compliance isssues
294
What can occur with abrupt cessation of a beta blocker?
angina, MI
295
What is a serious side effect of beta blocker usage in diabetic individuals?
blunts sympathetic nervous system response to hypoglycemia
296
What is an indication to give an oral alpha 1 blocker such as prazosin preoperatively?
resection of phenochromatoma
297
What drug class does clonidine belong to?
alpha2 agonist
298
How do treat ACE inhibitor inducted angioedema?
0.3-0.5mg of 1:1,000 epinephrine Subq
299
What type of cardiac issue contraindicates the use of clevidpine?
Aortic stenosis= decreased coronary artery perfussion
300
What is an example of a PDE5?
Sidenafil, tadalafil, vardenafil
301
What is the first line medication for SVTs?
Diltiazem; predominantly blocks cl channels in the AV node, slowing conduction
302
What calcium channel blocker should be avoided in patients with muscular dystrophy?
verapamil- skeletal muscle weakness
303
How does CRRT affect the half-life of milrinone?
increases; up to 20 hours
304
What is the drug of choice for fascicular VT?
Verapamil
305
What causes nitric oxide to become toxic?
When it is oxidized into nitric Dioxide
306
What can cause the development of cyanide toxicity to be more likely and why?
hypothermia/decreases enzymatic activity and greater accumulation of cyanide
307
What is an administration consideration for nitroprusside?
must be shielded from light
308
What happens with coronary steal?
increases ischemic area of MI
309
What is an administration consideration for amiodarone?
needs a micron filter
310
What is an administration consideration for nitroglycerine?
needs special non PVC plastic tubing
311
Nitroglycerine infusions shouldnt be given to patients with what cardiac disease?
hypertrophic obstructive cardiomyopathy & AS
312
What is the bolus dosage of amiodarone for VT/VF resistant to defibrillation?
300mg bolus
313
What compound do nitrites need to be active?
thio-compound
314
How should nitro tolerance be managed?
12-24 hour drug free period, rebound MI from drug free period can occur
315
what two electrolyte alterations cause an increase in the occurrence of ventricular fibrillation
hypokalemia
hypomagnesmia
316
What three things cause arrhythmias to occur?
1. reentry
2. enhanced automaticity
3. triggered
317
what rate increases risks of ventricular arrhythmias; brady or tachy?
brady
318
how do sodium channel blockers work?
decrease na influx, decrease conduction and velocity of the action potential
319
how to potassium channel blockers work?
prolong repolarization and duration of the AP/refractory period
320
class IA prodrug:
procanimide
321
class IB prodrug:
lidocaine
322
class IC prodrug:
Flecanide
323
class II prodrug:
beta blockers: metoprolol, labetolol, and esmolol
324
class III prodrug:
Amiodarone
325
What are the two prodrugs in class IV antiarrythmics?
verapamil and diltizam
326
What cardiac phase do class I antiarrythmics work on?
phase 0 depolarization
+ lidocaine phase 4
327
what are the effects of class I antiarrythmics on action potential?
classes IA and IC lengthen while class IB shortens
328
What causes torsades to occur during the cardiac phase?
early depolarization during delayed repolarization
329
what does bradycardia in the presences of a prolonged QT interval increase the risk of?
torsades event
330
what class of antiarrythmics treat incessant ventricular tachycardia?
Class IA and IC slow conduction enough
331
what classes of antiarrythmics treat wide complex tachycardias?
IC and III
332
in the setting of CHF, being on amiodarone long term can cause high risks of:
Vfib
333
what is the dosage for procanimide?
100mg IVP and 2-6mg/min
334
what are the toxic levels of procanimide and lidocaine?
p: >8mcg/ml
l: >5mg/ml
335
what does phenytoin treat cardiac wise?
decreases ventricular arrhythmias and torsades with dig toxicity
336
what is the dosage for phenytoin?
100mg/iv
337
how does phenytoin treat arrhythmia?
decrease automaticity and conduction
338
what are side effects of phenytoin?
CNS disturbances
339
What does flecainide treat?
ventricular and atrial/reenty arrythmias such as WPWS
340
What antiarrythmic class prevents the risk of sudden cardiac dealth?
Beta blockers
341
T/F the plasma level of amiodarone is higher than the level in the myocardium.
False, myocardial level is 10-50 times higher
342
What are the major side effects of chronic amiodarone use?
pulmonary toxicity/pheumonitis
343
What arrythmias can amiodarone cause?
torsades and other ventricular arrythmias
344
Can amiodarine induced bradycardia be treated with atropine?
No, it is resistant
345
Grayish blue slate skin discoloration occurs with chronic use of what drug?
amiodarone
346
What arrythmia can solotol cause?
torsades
347
What arrythmias do class IV treat?
Afib,flutter, WPWS
348
What cardiac phase do class IV antiarrythmias work in?
Phase 2 contraction
349
Verapamil dosage?
5-10mg
350
Diltiazem dosage?
20mg
351
What drug should never be given to a patient with WPWS and why?
Diltiazem, enhances conduction of accessory pathways
352
What is the dosage for Digoxin?
0.5-1mg in two doses in 24hr
353
Adenosine is an alternate to what medication for SVT?
CCBs
354
T/F Atrial fibbrilation is an indication for adenosine.
False
355
What is the dosage for adenosine?
6mg, 12mg, 12mg
356
What is the MOA of adenosine?
stimulates Adenosine receptors in cardiac muscle that increase intracellular potassium which causes a decrease in AP duration
357
What two things increase the effects of adenosine?
1. dipyridamole
2. transplanted heart
358
Is adenosine safe to use in a patient with WPWS?
yes
359
What is a frightening thing that occurs when administering adenosine?
transient heart block
360
How long is the half life of adenosine?
10 seconds, necessitating RAPID IV push
361
What antiarrythmic can alter thyroid function and why?
amiodarone, high percentage of iodine in the molecule
362
What can phenytoin NOT be mixed with?
D5W
363
What is the dose for IVP metoprolol
1-5mg
364
What drug should not be given to an individual taking PDE5s?
Nitroglycerin
365
What is the symatholytic of choice to use in an individual who takes PDE5s?
CCBs
366
What is the most common dysrhythmia that occurs in surgery and what is the frequency?
sinus arrythmia, 70%
367
What surgeries most commonly yield arrythmias?
cardiac and abdominal
368
Which volatile gas causes less QT prolongation/less risk of arrythmias?
Sevoflurene
369
Which inotrope is less effective in a transplanted heart?
dopamine
370
What drug should be used in a bradycardic emergency in a transplanted heart?
epinephrine and isoprenaline
371
What is the pneumotic that helps us remember antiarrythmic classes?
Some (sodium blockers)
Block (beta blockers)
Potassium (potassium blockers)
Channels (calcium blockers)
372
Calcium channel blockers are a ________ inotrope and should not be used in patients with ______ heart failure
negative, systolic
This indicates that it prolongs repolatization
373
374
what is the cardiac moa of epi?
increases stimulation of the AV node and decreases the refractory period
375
why does ephedrine have such a long duration or action?
it is resistant to MOA and COMT
376
what is the ivp dose of vasopressin?
1-2 unit
377
What is the preferred treatment for WPWS?
procainamide
Adenosine can be given while lidocaine cannot
378
What phases of the cardiac cycle are effected by class III antiarrythmics?
Phase 1 and 3
379
Where do class IV antiarrythmics work in the cardiac cycle?
mostly phase 2
phase 4 in pacemaker cells
380
Why do we want to shorten the AP (contraction/depolarization) and lengthen repolarizaion period with antiarrhythmics?
less time for ectopic beats to occur
381
where do class II antiarrythmics work in the cardiac cell?
Phase 4, pacemaker
phase 2, myocyte
382
What phase of the cardiac cycle do class 1 antiarrythmics work on?
Phase 0 in nonpacemaker
383
How does lidocaine work since it shortens AP while other sodium channel blockers lengthen the AP?
works on the conduction by decreasing conduction in the SA node to allow AV node to become the primary pacemaker at a lower rate
384
What is the ACLS dosage of vasopressin?
20 units
385
What is a contraindication for flecainide?
heart block
