What are the three ways that a heart attempts to maintain or improve CO by increasing stroke volume?
increasing heart rate via increased sympathetics, increased sympathetic tone increasing inotropy of the myocardium, increase proload that results in increased CO
What are the three ways that myocardial oxygen demand varies directly with?
heart rate, myocardial wall tension, iontropic state
what is the target for loop diuretics?
sodium, potassium, and chloride reabsorption in the thick ascending loop of Henle
what is the mechanism of action of the loop diuretics?
bind to the Na, K, 2 Cl- symporter and prevent the binding and moving of ions into the cell
What is an awful place to put loop diuretics or any cardiac drug for that manner?
SQ or transdermally
when is the peak of diuretic activity of furosemide and what is its classification?
1 to 1.5 hours; loop diuretic
what are the side effects of loop diuretics in terms of electrolytes?
hyponatremia, hypochloremia, hypokalemia
what is the mechanism of action of thiazide diuretics?
inhibition of sodium reabsopriont within the DCT
What is the other common name that thiazide diuretics are called and why is it given this name?
calcium sparing diuretics; less calciuresis takes place with this drug
When you have a patient with ascites with right sided heart failure or biventricular failure what is the common drugs used?
loop diuretic in combination with thiazide diuretics
what are the kidney effects of cardiac thiazide diuretic drugs?
increased excretion of sodium, potassium ,and magnesium; overall increase in urine volume; significant loss of potassium (major side effect)
what is the mechanism of action of potassium sparing diuretics?
works in the DCT and collecting ducts by antagonizing aldosterone effects.
a drugs that is antimitogenic through aldosterone antagonism and is converted mainly by hepatic transformation to its active form canrenone
Why is reducing afterload important and what disease is it associated with mainly?
reducing afterload allows reduced cardiac work and increased stroke volume/cardiac output; This is used mainly with patients with mitral regurgitation (REGURG VOLUME CAN BE REDUCED AND WILL INCREASE FORWARD STROKE VOLUME AND REDUCE THE SIZE OF THE LEFT ATRIUM AND LEFT ATRIAL PRESSURE)
when is it warrented to absolutely not use vasodilators?
when the blood pressure is less than 70mm Hg
What is the main mechanism of action of alodipine
vasodilator; peripheral calcium channel blocker calcium induced calcium release is being stopped
What is the proposed mechanism of action of venous vasodilators?
spontaneous release of NO activating smooth muscle guanylyl cyclase to form cGMP. cGMP inhibits calcium entry into the cell-->decreases intracellular calcium concentration cause smooth muscle relaxation; NO can also activate potassium channels leading to hyperpolarization and relaxation. NO acts through cGMP and can stimulate cGMP dependant protein kinase that activates myosin light chain phosphatase (dephosphorylates myosin light chains which leads to relaxation)
What are two vasodilators used in vet med?
nitroglycerin ointment (topical only); isosortbide dinitrate
What are the storage conditions of nitroprusside
light sensitive, discard in 4 hours, place in normal saline
what is the mechanism of action of hydrochlorothiazide?
inhibition of the sodium chloride symporter on the distal convoluted tubule