Sympathomimetic- Epinephrine Flashcards
direct acting synthetic non catecholamines
phenylephrine
methoxamine
indirect acting synthetic non-catecholamines
ephedrine
mephentermine
amphetamine
metaraminol
synthetic catecholamine
isoproterenol
dobutamine
what drug is the prototype of all sympathomimetics
epinephrine
where is epi synthesized, stored, and release from
the adrenal medulla
epinephrine regulates 6 things. name these 6 things
myocardial contractility heart rate vascular smooth muscle tone bronchial smooth muscle tone glandular secretions metabolic process (glycogenolysis, lipolysis)
is Epi a CNS stimulant
no
what make up of epi makes it a poor CNS stimulant
poorly lipid soluble
what receptor activation accounts for EPI cardiovascular effects
alpha and beta
how does epi affect renal blood flow
substantially decreased- even in the absence of systemic blood pressure changes
how much more potent is epi to NE as a real vasoconstrictor
2-10x
higher doses of EPI affect which receptor
alpha receptors
lower doses of epi affect which receptor
beta receptor
high doses of epi- alpha activity create what
vasoconstriction increased afterload
epi HR effects
initial tachycardia followed by HR decrease due to baroreceptor reflexes
increase CI & SVR from EPI leads to
increase blood pressure
EPI stimulates b1 receptors which increases 3 things
HR contractility and co
what happens to diastolic BP in the presence of EPI
mild decrease reflects vasodilation in skeletal muscle vasculature due to stimulation of beta 2 receptors
increases in HR associated with EPI accelerates which phase
phase 4
which epi stimulates phase 4 what are you at risk for
cardiac dysrhythmias
is tachyphylaxis seen with epi
no
what effects does EPI have through the heart
increases conduction velocity, decreases refractory period in AV node, bundle of HIS, purkinje fibers and ventricular muscle
EPI causes what effect to myocardial oxygen consumption
increased with enhanced LV preload, increase contractility increased after load and tachycardia
epi and diastolic function?
improved diastolic function by increasing the rate of myocardial relaxation
EPI effects of coronary blood flow
NE effects of coronary blood flow
Phenylephrine effects of coronary blood flow
epi increases-do not alter systemic bp
NE- no affect on coronary blood flow
phenylephrine- increases coronary blood flow
how to you block the hemodynamic effects of EPI
administration of alpha or beta adrenergic receptor antagonist
name the 5 things supra therapeutic doses of EPI can lead to
pulmonary edema acute heart failure arrhythmias hypertension myocardial ischemia
what is the EPI effect of beta 2 activation
smooth muscles of the bronchi relaxaing
when epi stimulates beat 2 in relation to asthma - what release is decreased?
vasoactive mediators.
if the patient is beta blocked and given EPI what effects are seen in the lungs
bronchoconstriction - from stimulation of bronchial alpha receptors.
of all catecholamines EPI has the most significant effect on _____
metabolism
epi beta receptor effect on metabolsim
increase liver glcogenolysis and adipose tissue lipolysis
Epi and alpha 1 receptor affects on metabolism
inhibits release of insulin
EPI infusion usually increases the concentration of what 4 things
glucose
cholesterol
phospholipids
low density lipoproteins
why do patients experience perioperative hyperglycemia
endogenous epi release results in inhibition of insulin secretion and glycogenolysis and inhibits peripheral glucose uptake
Epi induced hypokalemia may contribute to what?
cardiac dysrhythmias
EPI is also responsible for the release of what electrolyte from the liver
potassium- tending to offset the decrease in extracellular concentration of potassium produced by entrance into the skeletal muscle
explain the two different reasons for increase concentration of lactate as seen with EPI administration
- may reflect epi induced glycogenolysis in skeletal muscles
- transient increase due to inhibition of pyruvate dehydrogenase and has no relationship with cellular hypoxia and tissue perfusion nor is it associated with metabolic acidosis
what is the reason for low potassium levels associated with EPI
beta 2 adrenergic agonist activate the sodium potassium pump
during induction what does the endogenous release of EPI do to your electrolytes
decrease potassium level
what can we give preop to prevent hypokalemia
propranolol may prevent hypokalemia
what is the concern with cardioselective beta 1 antagonist atenololol
may cause hypokalemia
what two things do you see with the eye when administering EPI
which receptor is responsible for this
mydriasis and exophthalmos
alpha receptors
contraction of radial muscle of the iris producing mydriasis
contraction of the orbital muscles produces and appearance of exopthalmos
what three medication produce gi relaxation of the smooth muscles
EPI, NE, isoproterenol
Epi activates beta adrenergic receptor to do what with the bladder
relaxes the detrusor muscle of the bladder
EPI activation of alpha receptors contracts the trigone and sphincter muscles. meaning what exactly
stretch muscles signaling the brain the need to empty
what coagulation effects are seen with EPI
platelet aggregation and increase factor V activity- hypercoaguable state in intro and post op reflect stress associated release of EPI
what labs on the CBC are changed with EPI
increases leukocyte count
eosinopenia
EPI effects of the Liver
hepatosplanchnic vasoconstriction
renal effects with EPI
impaired renal blood flow as co is diverted to dilated skeletal muscles.
stimulates renal beta receptors resulting in what
increase secretion of renin
EPI receptors
a1 a2 b1 b2
EPI general uses (from chart)
Anaphylaxis, glaucoma (open angle) asthma, hypotension with LA
EPI administration forms
Sub q, Iv or IM
absorption of EPI sub q
slow
