Kyle Lecture Vasopressors/inotropes Flashcards
Catecholamine synthesis
Tyrosine
TH
Dopa
AADC
Dopamine
DBH
Norepinephrine
PNMT
Epinephrine
How are you going to fix bradycardia if the patient is hypertensive
Glycopyrrolate 0.2
Emergency-atropine
Beta agonist MOA (WEEDS)- in cardiac myocyte
Binds BAR
Upregulates cAMP
Activating PKA
Causes increased calcium influx and release from SR
Role of calcium in myocardial contractility
Direct interaction with cardiac troponin (actin)
Causes binding’movement of myosin head
Beta Agonism (weeds) smooth muscle
cAMP and PKA block calcium influx!!
=Vasodilation via B2
Vascular smooth muscle contraction
Increased calcium
Calcium binds camodulin
CaM- activates myosin light chain kinase
MLCK phosphorylates the myosin light chain
This creates a cross bridge and creates contraction
What is present in myosin light chain contraction
Phosphate
What is myosin light chain without phosphate?
Relaxed
Difference between Beta agonism in the heart VS VSM
Heart- brings in Ca
VSM- blocks Ca
Role of IP3 in Alpha activation
Calcium release from endoplasmic reticulum
DAG
Alpha activation of smooth muscle
Activates protein kinase C
Which leads phosphorylation of MLCs=contraction
Adverse effects of Epinephrine
Hyperglycemia
Hypokalemia
Lactic acidosis
Myocardial ischemia
Epi Dosing
Moderate hypotension-5-10 mcg
Infusion 0.02-0.3 mcg/kg/min
Low dose epi if<0.05 vasodilation due to B2
Higher doses see predominately alpha 1
What will you see with low dose Epi
Beta 2 vasodilation
See alpha vasoconstriction at higher doses
Impact of norepinephrine on CO and HR
NOTHING
CO may decrease
Dopamine Dosing
Low dose 0.5-3 mcg/kg/min RENAL
Moderate 3-10 mcg/kg/min Beta 1
High 10-20 mcg/kg/min Alpha 1
List 3 inodilators
Dobutamine
Isoproterenol
Milrinone
When will you see Isoproterenol and what are 2 adverse effects
Stress echo- PUUUUUre Beta stimulation
Tachycardia/palpitations
Flushing
What impact does milrinone have on adrenergic receptors?
Trick question, fuck you its a PDE3 inhibitor that increases cAMP and therefore Ca in the myocardium
Dosing phenylephrine
5-200 mcg
0.2-2 mcg/kg/min
Hypotension in setting of spinal in C-section?
Phenylepherine
Previous recommendation was ephedrine
Considerations and effects for phenylephrine
Do you have a heart rate? You really need a heart rate Jack
Severe Reflex bradycardia with pure alpha stimulation
What’s your indirect/direct agent?
Ephedrine 5-10 mg
Dosing Vasopressin
Low and slow
0.5-2 units… probs just 0.5 units
Reflex bradycardia
Electrolyte abnormalities you will see increased digoxin toxicity
Hypokalemia
Hypomagnesemia
Hypercalcemia
RAAS
Renin release
Conversion of angiotensinogen to angiotensin I in Liver
Conversion Via ACE to angiotensin II which is our vasoactive molecule
Angiotensin receptor stimulation
Vasoconstriction
Salt retention
Vascular growth
Which is the only cardiac med we have people hold before surgery?
ACE-I
ARAs
What do you give in setting of refractory hypotension in patients on an ace inhibitor?
Vasopressin
Impact of nitroglycerin on vasculature
VENO dilation
Liver decongestant
Do not give in PRELOAD dependent states (right sided MI)
What do Beta blockers depress?
Central vasomotor center in the brain
Heart
Renin release from the kidney
What patient population are we cautious with beta blockers?
Asthmatics
B2 inactivation causes bronchoconstriction
Which beta blocker causes the release of nitric oxide
Nebivolol
Which beta blocker has alpha antagonism effects?
LAbetolol
Selective Beta blockers
Metoprolol
Esmolol
Atenolol
Nebivolol
Biosprolol
Nonselective beta blockers
Labetolol
Carvedilol
Propranolol
Nadolol
Sotalol
What do you give with HTN and a high heart rate?
Metoprolol
What do you give with hypertension and a normal heart rate?
Labetolol
What do you give with normotensive patient with high heart rate?
A beer
Esmolol
CCB with most cardiac effects
Verapamil
Best drug to give to lower SVR in patient with LV systolic dysfunction and an EF<30
Amlodipine
Metabolism of clevidipine
Nonspecific esterases
Selective alpha blockers
Prazosin
Indoramin
Terazosin
Doxazosin
Nonselective alpha blockers
Phentolamine
Phenoxybenzamine
Difference between phenoxybenzamine and phentolamine
Phenoxybenzamine is a non competitive antagonist- long duration of action
Only time you will maybe give an alpha blocker
Pheocryocytoma?
Hyperplasia of adrenal medulla and exaggerated sympathetic response
What to give in low heart rate high BP
Hydralazine
What’s your only venodilator
Nitroglycerin
What drug acts on venous an arteriolar
Nitroprusside
What is the defining factor of hypertensive emergency?
End organ damage
Overall… according to Kyle… what does alpha 2 agonism do?
Vasodilation
Despite some postsynaptic alpha2B mediated vasoconstriction in the periphery
Isosorbide metabolism
Hepatic, 5-6 hours
Longer angina relief than. Nitro
Digoxin toxicity
2-3rd degree block
Bradycardia
Ventricular arrhythmias
N/V
Visual changes
Electrolyte imbalances that increase digoxin toxicity
Hypokalemia
Hypercalcemia
Drugs that increase Digoxin levels
Amiodarone
Verapamil
Quinidine
Macrolide antibiotics
