Cardiac Drugs Flashcards
T/F: Diuretics are also known as water pills
T
Diuretics block Na reuptake in nephrons, helping excrete water via urine
T/F: Class III antiarrhythmic drugs are calcium-channel blockers that slow the HR by slowing electrical impulses.
F
Class III antiarrhythmic drugs are K-channel blockers that work by slowing electrical impulses in all heart cells, whereas Class IV antiarrhythmic drugs are the Ca-channel blockers.
Amlodipine and nifedipine are examples of Ca channel blockers
T
T/F: Beta-blockers dilate blood vessels to allow for a better flow of O2.
F
Beta-blockers decrease cardiac output by slowing the HR and decreasing force of contraction, whereas vasodilators dilate the blood vessels and allow better flow of O2 to the heart muscles, thus reducing workload on the heart.
T/F: Blood thinners are coagulation agents
F
They are ANTI-coagulation agents
T/F: Cardiovascular drugs like Na-channel blockers, beta-blockers, and Ca-blockers can cause arrhythmias.
F
Theses are ANTI-arrhythmics, so they help to stop arrhythmias.
Depolarization is the ___________ of the impulse, while repolarization is the __________ of the impulse.
contraction
relaxation
Depolarization is the ___________ of the impulse, while repolarization is the __________ of the impulse.
contraction
relaxation
____ is most involved in depolarization of the heart.
Na
_____ is most involved in repolarization of the heart.
K
What are the 4 receptors that the Sympathetic NS uses?
Alpha-1
Alpha-2
Beta-1
Beta-2
What are the substrates for the Sympathetic NS receptors?
epinephrine
norepinephrine
What happens when Beta-1 receptors are stimulated?
heartbeat increases
HR increases
depolarization wave increases
cardiac muscle contraction increases
What happens when Beta-2 receptors are stimulated?
smooth muscle relaxes which produces vasodilation of arterioles and greater blood flow to skeletal muscles
dilates bronchioles allowing more airflow
What happens when the Alpha-1 receptor is stimulated?
- Smooth muscle constricts
- Vasoconstriction of arterioles
- Increased resistance of flow for small arterioles, so more blood gets shunted to skeletal muscle
- Increased workload on heart
What happens when Alpha-2 receptors get stimulated?
When enough NE gets released to stim the target receptor, stimulation of alpha-2 receptors gets shut down so you don’t get too much of it released
What do Na channel blockers do?
Block fast Na channels that allow Na influx into the cell, thus depolarization is delayed (meaning the refractory period gets extended)
What drugs are Na-channel blockers?
Lidocain
Mexiletine
Procainamide
Quindine
What do beta-blockers do?
block beta-1 receptors so NE cannot bind to them and stimulated HR
What do all beta-blocker drugs end in?
-olol
What do potassium channel blockers do?
Slow electrical impulse conduction in all heart cells
What do Calcium channel blockers do?
- slow HR by slowing electrical impulse conduction at SA and AV nodes
- prevents Ca from entering cells of heart and blood vessel walls
Calcium channel blocker drugs
amlodipine
diltiazem
verapamil
What type of cardiac drugs are Na-channel blockers, beta blockers, K-channel blockers, and Ca-channel blockers?
Antiarrhythmics
What is a positive inotrope?
a type of drug that increases the force of contraction of the heart
What do positive inotropes do to increase the force of contraction of the heart?
They either increase the Ca that’s available to the contractile elements of the cardiac muscle cells (so more Ca is present for use) or they increase the affinity of Ca for combining with the contractile elements (so muscle cells are more responsive to the Ca that is present)
What is an inodilator?
It is like a positive inotrope, but it also dilates the arterioles (small arteries just before the capillaries) which reduces resistance to blood flow and reduces the workload on the heart
List the 4 catecholamines
epinephrine
NE
dobutamine
dopamine
What do catecholamines do?
Stimulate Beta-1 and Alpha-1 receptors
What type of drug is pimobendan, and what does that mean for how it works?
positive inotrope and inodilator
so it increases strength of contraction and dilates arterioles
What type of drug is digoxin?
positive inotrope and antiarrhythmic
What are the 3 ways a vasodilator can work?
- block Alpha-1 receptors (so vasoconstriction can’t happen)
- block renin-angiotensin system (angiotensin II isn’t made, so it can’t cause vasoconstriction)
- direct relaxation of arterial smooth muscle
What is the overall purpose/goal of using vasodilators?
to attempt to reduce resistance to blood ejection from the heart and thus also reduce the heart’s workload. Essentially, you’re trying to reduce hypertension.
What drugs should vasodilators NOT be combined with and why?
Beta-Blockers
b/c vasodilators dilate arteries and cause hypotension. The boy will try to react to the hypotension by activating the sympathetic NS. SNS will release NE, but NE won’t be able to bind to Beta-1 receptors to elevate the blood pressure because the beta blockers block Beta-1 receptors.
Difference between selective and non-selective beta-blockers.
Selective block only beta-1 receptors, where non-selective block both beta-1 and beta-2 receptors.
List drugs that are considered vasodilators
amlodipine hydralazine nitroglycerin nitroprusside ACE Inhibitors
What do ACE inhibitor drugs end in?
-pril
What are the 4 functions of diuretics?
reduce accumulation of tissue fluid (edema)
reduce blood volume (remove water)
reduce arterial blood pressure (b/c decreasing blood volume)
decrease workload on failing heart in CHF
How does the general diuretic work?
prevents reabsorption of (x) from the urine. This increases the number of particles in the urine, thus increasing osmotic force that holds water in the urine so water leaves in the urine
What is the loop diuretic commonly used?
Furosemide
What diuretic is used secondarily? What do those drugs end in?
Thiazide diuretics
-thiaside
How does spironolactone work?
It is a diuretic that blocks aldosterone. Because of where this acts, Na will remain in the urine and be lost from the body, but K will be retained. This is different, as Furosemide ends up exchanging Na for K, so K gets lost from the body and Na is retained.
Aldosterone usually causes ____ to be reabsorbed from the urine.
Na
