Exam 4 - Cardiovascular Pharmacology Flashcards
electrical malfunction - _________
valve leakage - _______ _______
pump failure (cold) - ______________
congestive heart failure - ________
vessel abnormalities (narrow or blocked) - ________
electrical malfunction - arrhythmias
valve leakage - valve disease
pump failure (cold) - cardiomyopathy
congestive heart failure - drowning
vessel abnormalities (narrow or blocked) - hypertension
what are the goals in using drugs to treat cardiovascular disease?
control arrhythmias, resolve congestion, improve contractility, resolve clinical signs, & maintain/improve quality of life
T/F: drug interactions are possible & likely in cardiovascular drugs
true
what is preload?
pressure stretching the ventricle of the heart after passive filling of the ventricle & subsequent atrial contraction (volume)
what are some drugs that are preload reducers?
diuretics!!!!
nitroglycerine paste & ace inhibitors
what is the difference in clinical signs between left & right sided heart failure?
left sided - pulmonary edema
right sided - ascites
what is the mechanism of action of loop diuretics?
inhibit the highly reabsorptive NaKCl co-transporter in the ascending limb of the loop of henle & cause potassium wasting
what are the adverse effects of loop diuretics?
dehydration & electrolyte abnormalities
what drugs are commonly used loop diuretics for cardiac disease?
furosemide & torsemide
what kind of drug is spironolactone?
aldosterone receptor antagonist
what is the mechanism of action of spironolactone?
blocks Na & K transport in the distal tubule & collecting ducts leading to Na excretion
antifibrotic effect by blocking RAAS
potassium sparing
what is the diuretic effect of spironolactone?
minimal
what is the mechanism of action of hydrochlorothiazide?
inhibits the reabsorption of Na & Cl in the distal tubule & causes potassium wasting
what are the adverse effects associated with hydrochlorothiazide?
dehydration & electrolyte abnormalities
label the drugs that work at each number
- loop diuretics
- thiazides
- spironolactone
what is an inotrope?
agent that alters the force of the heart muscle contraction
what do negative inotropic agents do?
decrease the force of muscular contraction
what do positive inotropic agents do?
increase the strength of muscular contraction
what are some examples of negative inotropic drugs?
beta blockers & calcium channel blockers
what are some examples of positive inotropic drugs?
dobutamine!! - IV
pimobendan! - PO
digoxin - PO
what is the mechanism of action of pimobendan?
positive inotrope - calcium sensitization & PDE III inhibitor that causes balanced arterial & venous vasodilation
leads to improved forward blood flow
what is afterload?
pressure the left ventricle has to generate in order to eject blood into the aorta - the pressure in the ventricle must be greater than the systemic pressure in order to open the aortic valve
what are some examples of drugs that are afterload reducers?
amlodipine & telmisartan
hydralazine
ace inhibitors
what is the ideal blood pressure?
110-120 mmHg
what happens if you have a blood pressure < 90 mmHg?
clinical evidence of low cardiac output, weak & lethargic animal, & need to use careful administration of any afterload reduced
what happens if you have a blood pressure > 160 mmHg?
monitor patient for evidence of end organ damage & afterload reduction
what is the primary effect of antihypertensive medications?
lower blood pressure
what drug is used in both dogs & cats to lower blood pressure?
amlodipine - calcium channel blocker
what drug is used in cats to lower blood pressure?
telmisartan - semintra, angiotensin II receptor blocker
what drug is used in dogs to lower blood pressure?
hydralazine
what is the equation of blood pressure?
blood pressure = cardiac output X systemic vascular resistance
T/F: pimobendan is an antihypertensive medication
false - positive inotrope & vasodilator
what drug is commonly used as an additional effect for antihypertension?
ace inhibitors - enalapril & benazepril
may decrease BP by 5-10 mmHg, but it’s not typically used as a monotherapy for systemic hypertension
when looking at calcium channel blocking drugs, between DHPs & NON-DHPs, which is more vascular selective?
DHPs - more vascularly selective
NON-DHPs - act equally on the heart & the arterioles
what are examples of DHPs & NON-DHPs drugs?
DHPs - amlodipine
NON-DHPs - diltiazem
what neuroendocrine response does the body have to cardiac disease?
maladaptive response from the RAAS cascade & sympathetic nervous system
what is the RAAS cascade?
hormone system that regulates blood pressure & water balanced with end products of angiotensin II & aldosterone
promotes vasoconstriction & sodium/water retention
what drugs are used as a blockade to the RAAS cascade?
ace inhibitors, anti-aldosterone, & angiotensin II blockers
what effects are seen in the sympathetic nervous system in response to cardiac disease?
constant adrenergic stimulation to the heart - B1 down regulates, but B2>B1
becomes counter productive in heart failure - b mediated tachycardia & a mediated vasoconstriction
what drugs are used for a blockade of the sympathetic nervous system when a maladaptive response is present due to cardiac disease?
selective (atenolol) beta blockers or non-selective
negative chronotropes/inotropes
only use these in STABLE PATIENTS
what are chronotrophic drugs?
drugs that change the heart rate and/or rhythm
what do positive chronotropes do?
increase heart rate - anticholinergics (atropine, glycopyrrolate)
what do negative chronotropes do?
decrease heart rate & reduce arrhythmias - beta blockers & calcium channel blockers
these drugs typically have other important effects (negative inotrope)
do patients with DCM have a decrease or increase in ventricular muscle contractility?
decrease - need a positive inotrope
where do patients with left-sided heart failure accumulate fluid?
pulmonary edema - need a drug to reduce preload
what neuroendocrine system are activated in heart failure?
RAAS - need to block RAAS activation
what is congestive heart failure?
condition that can result from any structural or functional cardiac disorder that impairs the ability of the heart to fill with or pump a sufficient amount of blood throughout the body
what is DCM?
condition in which the heart becomes weakened, enlarged, & cannot pump blood efficiently
what drugs are useful for ventricular arrhythmias?
lidocaine, procainamide, sotalol, & amiodarone
what drugs are useful for both supraventricular & ventricular arrhythmias?
procainamide & quinidine
