Inotropes Flashcards
Discuss the hemodynamic profile of the phosphodiesterase III inhibitors amrinone and milrinone.
Increasing cardiac output through increased inotropy and improved lusitropy (myocardial relaxation)
What untoward effects can result from use of phosphodiesterase inhibitors?
Vasodilation
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Prolonged use of amrinone may result to?
Thrombocytopenia
This drug is an extremely potent b1- and b2- agonist that possesses no a-stimulating properties.
Isoproterenol
What nitrovasodilator becomes degraded to cyanide and may cause toxicity?
Sodium nitroprusside
Site of action
1) Sodium nitroprusside
2) Nitroglycerin
1) Arteries
2) Veins
Benefits of nitroglycerin (3)
1) Improved coronary perfusion
2) Decreased O2 demand
3) Antiplatelet
What nitrovasodilator is confounded with tachyphylaxis?
Nitroglycerin & nitroprusside
Because of changes in the enzymatic machinery responsible for its transformation into NO
What is the therapeutic ceiling dose of nitroprusside?
2 mcg/kg/min
This vasodilating agent relaxes smooth muscle, dilating arterioles to a much greater extent than veins and decreasing diastolic more than systolic blood pressure.
Hydralazine
Onset 15 to 20 mins
Reflex tachycardia
This drug is a short-acting selective calcium channel blocker (CCB) that acts on the arteriolar beds, providing easier titration and controlled reduction in systemic blood pressure.
Nicardipine
This drug is becoming the arterial vasodilator of choice for cardiac surgery patients with hypertension since it has more selective coronary vasodilation than systemic vasodilation.
Nicardipine
Onset: 5 to 15 mins
Duration 4-6 hours
This drug is a new third-generation CCB that is considered an ultrashort-acting arteriolar vasodilator
Clevidipine
Half-life of clevidipine
2 minutes
Is a unique parenteral vasodilator that acts via peripheral dopamine-1 receptors. This has a vasodilatory effect that is selective for renal and splanchnic vasculature and causes mild renal diuresis.
Fenoldopam
Arginine vasopressin (AVP) has action at three subtypes of receptors (V1, V2, and V3).
Which receptor stimulates vascular smooth muscle contraction, resulting in the vasopressor response
of AVP?
V1
This arginine group of receptors primarily act in the kidney to produce water retention (antidiuretic
hormone).
V2
This arginine group of receptors act in the central nervous system, and modulate corticotropin secretion.
V3
Congestive heart failure in the presence of preserved left ventricular systolic function (ejection fraction [EF] >35%) and the absence of ischemia and valvular pathology suggests?
Diastolic heart failure
Is a pyridazinone-dinitrite and a member of a new class of pharmacologic agents, the “calcium sensitizers.” This drug acts to increase contractility without elevating intramyocardial calcium levels. This is achieved by stabilizing troponin C in an active form, thus providing inotropic support in similar fashion to other agents but with much lower intracellular calcium requirements.
Levosimendan
