Week 1 Cardiac Pharmacology and Autonomic 1 of 4 Flashcards
Sympathomimetic Amines
- Name Naturally occurring catecholamines:
- Name synthetic agents:
-Naturally occuring:
Epinephrine, norepinephrine, and dopamine
- synthetic agents:
Phenylphrine and dobutamine
Epinephrine Strongly stimulates
- both B1 and B2 receptors
Epinephrine Treats:
Treatment:
- Anaphylaxis
- Cardiopulmonary resuscitation
- Treatment of shock with poor tissue O2 delivery and hypotension are combined (this is b/c of its alpha and beta effects)
____ May be useful as a sympathomimetic agent in patients unresponsive to indirect-acting agents and in those in whom simultaneous Beta 1 (cardiac stimulation) and Beta 2 receptor stimulation (vasodilation).
Epinephrine
Dominance of alpha or beta effects is dose related in what sympathomimetic?
epi
Epi Beta 1 produces + or - :
- inotropic
- Chronotropic
- dromotropic
+ inotropic
+ chronotropic
+ dromotropic
inotropic
(force of contraction)
chronotropic
(heart rate)
dromotropic
(conduction velocity)
As HR, LV Stroke work, SV, and CO increase, what also increases?
Myocardial O2 consumption
Because of increased automaticity of all foci (including those that are ectopic) there is a possibility of:
arrhythmia
to ensure that an imbalance of myocardial oxygen supply and demand does not occur requires:
vigilance
Epi Beta 2 stimulation:
- Bronchodilation
- Vasodilation
- Stabilization of mast cells (resulting in decreasing histamine release)
- Concurrent alpha stimulation promotes a decrease in bronchial secretion. Net effects are a decrease in airway resistance with an improvement in oxygenation
-Stabilization of mast cells results in
decreasing histamine release
-Concurrent alpha stimulation promotes a decrease in bronchial secretion. Net effects are
a decrease in airway resistance with an improvement in oxygenation
Epinephrine - Low Doses 10 mcg/min:
The peripheral vasculature promotes the redistribution of blood flow to skeletal muscle, thus producing
a decrease in SVR
As epinephrine doses increase, alpha effects
predominates
-resulting in vasoconstriction and increased SVR
increasing epi doses do what do SBP, DBP and Pulse Pressure
- SBP increases
- DBP remains relatively unchanged
- Pulse Pressure increasesq
(in regards to Epi) If coronary arteries are not obstructed, autoregulation
increases O2 delivery to meet the increase in demand
(in regards to Epi) If coronary arteries are obstructed
O2 delivery may be insufficient to meet demand resulting in myocardial ischemia
(Epi) increases in alpha effect also causes what in relation to abdominal organ blood flow and renal blood flow?
- Splanchnic vasoconstriction
- Renal vasoconstriction: Renal vascular resistance and ultimately renal blood flow are decreased
Beta stimulation (with epi) leads to activation of: (think kidneys)
the renin-angiotensin system
Beta Stimulation (with epi) increases what metabolic effects?
- lipolysis
- glycogenolysis
- gluconeogensesis
- ketone production
- lactate release by skeletal muscle
alpha or beta stimulation effect:
Splanchnic vasoconstriction
alpha
alpha or beta stimulation effect:
renin-angiotensin system
beta
alpha or beta stimulation effect:
lipolysis
beta
alpha or beta stimulation effect:
gluconeogensesis
beta
alpha or beta stimulation effect:
renal vasoconstriction
alpha
alpha or beta stimulation effect:
keytone production
beta
alpha or beta stimulation effect:
lactate release
beta
With epi, what receptor is stimulated to cause a decrease in insulin?
Beta 2 stimulation
Epinephrine induced beta 2 stimulation can cause a transient :
hyperkalemia
as potassium follows glucose out of the hepatic cells
Epinephrine induced beta 2 stimulation also causes a longer ____. Why?
hypokalemia
b/c beta 2 stimulation forces K (extracellular) into the RBC
What is a:
- Potent vasopressor
- Not as potent as epi in stimulating alpha receptors in equal doses
- Has little Beta 2 activity at low doses
- Has for the most part unopposed alpha stimulation
- Chronotropic activity seen with Beta 1 stimulation is generally absent in low doses
- This is because of increase in SVR which includes reflex vagal activity
Norepinephrine
Norepi’s adrenergic stimulation results in a decrease in
vital organ blood flow
Coronary artery perfusion (with norepi) may be:
increased
-b/c of the increase in DBP
Increased renal vascular resistance (with Norepi) may cause:
UOP to fall
due to norepi’s vasoconstriction properties, preload may
increase
Norepi is first line therapy for:
shock (as is dopamine)
Norepi is generally used in patient with adequate:
Cardiac Output but low SVR
Norepi may exacerbate what issues even though BP is adequate?
What is the cause of this?
- Tissue perfusion oxygenation issues
- by intense peripheral vasoconstriction
What might we see norepi do to insulin production?
decrease insulin production
Metabolic effects of epi and norepi (greater and less)
epi > norepi
Endogenous central and peripheral neurotransmitter
Dopamine
is derived from dopa in the chain of catecholamine synthesis
Dopamine
Dopamine Dose that dependently stimulates Dopamine receptors:
2 mcg/kg/min
Dopamine Dose that dependently stimulates Beta receptors:
2-5 mcg/kg/min
Dopamine Dose that dependently stimulates Alpha receptors:
10mcg/kg/min and above
Dopamine also has indirect sympathomimetic effect eliciting the release of
norepinephrine via Beta-1 stimulation
Dopamine has an indirect or direct sympathomimetic effect eliciting the release of norepinephrine?
indirect
What receptor does dopamine stimulate to elicit norepi release?
beta-1
Dopamine is often first chose for patients in:
shock
Dopamine also inhibits what mineralcorticoidsteroid?
Resulting in an increase in:
inhibits: aldosterone
an increase in: sodium excretion and UOP
Dopamine has been implicated in limb ischemia in: (patient population, patients with certain diseases)
- Pediatric patients
- vascular diseases: DM, Atherosclerosis, Raynaud’s
- Art-line in affected limb also increases incidence of limb ischemia w/concurrent dopamine gtt
Isoproterenol
- MOA information
- synthetic catecholamine
- Potent non-selective agonist of B1 and B2 receptors
Has no agonist activity at alpha or dopamine receptors:
isoproterenol (and also dobutamine)
Uses of Isoproterenol:
- Brady w/HB
- Torsades VT
- after Heart transplant for chronotropic support (B2 stimulation)
*limited use since dobutamine and milrinone emergence
