Cardiovascular Drugs Flashcards
What is preload?
Pressure exerted on the heart ventricle
Animals on IV fluid therapy can lead to an _____ blood volume and therefore an ______ preload
Animals of IV fluid therapy can lead to an increased blood volume and therefore an increased preload
An increased venous blood pressure will cause an ______ preload
An increased venous blood pressure will cause an increased preload
What can cause an increase in venous blood pressure?
Vasoconstriction
Increased blood volume
What happens to the blood volume when there is a reduced cardiac output in an animal?
Increased blood volume
Vasoconstriction
The ____ the preload, the _____ the heart needs to work due to increased workload
The higher the preload, the harder the heart needs to work due to an increased workload
What is afterload?
Pressure the heart must produce to overcome arterial pressure to open the valves and eject blood into the artery
An increase in arterial blood pressure will ______ afterload.
An increase in arterial blood pressure will increase afterload
Hypertension decreased afterload. True/False?
False - increases afterload
What are inotropic medicines aimed at improving?
Heart contractility
What are antiarrhythmic medicines aimed at restoring?
Normal heart rate and rhythm
What are vasodilator medicines used to reduce?
Peripheral resistance
What do diuretic medicines work to remove?
Fluid accumulation
What type of inotropic drug is pimobendan?
Positive inotropic
Although Pimobendan is an inotropic medicine, it also acts as a vasodilator. True/False?
True
What enzyme does pimobendan inhibit in the cardiac muscles?
Phosphodiesterase
What is the main +ve inotropic mechanism of pimobendan?
Increases sensitivity of heart contractile proteins to existing levels of intracellular calcium
Digoxin is a positive inotropic medicine. True/False?
True
Digoxin has a ______ therapeutic index
Digoxin has a narrow therapeutic index
What is Digoxin’s mechanism of action?
Inhibits the Na+K+ATPase pump in the cardiac muscles
Digoxin also has a negative chronotropic effect. True/False?
True
ACE inhibitors have a wide therapeutic index. True/False?
True
What does ACEI stand for?
Angiotensin converting enzyme inhibitors
ACE inhibitors interfere with the effects of _______.
ACE inhibitors interfere with the effects of aldosterone
ACE inhibitors stop the formation of _______
ACE inhibitors stop the formation of angiotensin II
ACE inhibitors decrease preload and afterload. True/False?
True
By inhibiting the formation of angiotensin, ACE inhibitors reduce _________
By inhibiting the formation of angiotensin, ACE inhibitors reduce vasoconstriction
ACE inhibitors cannot be given orally. True/False
False - safe and often given orally
Name 3 ACE inhibitor drugs
- Benazepril
- Enalapril
- Ramipril
Name 2 possible side effects of ACE inhibitors.
- Hypotension
2. GIT symptoms
ACE inhibitors are use for a short term period. True/False?
False - long term/lifetime treatment
Calcium channel blockers have the broadest actions of al cardiovascular medicines. True/False?
True
What type of inotropic agent are calcium channel blockers?
Negative
What type of chronotropic agent are calcium channel blockers?
Negative
Calcium channel blockers also act as vaso_____ and are used as a________
Calcium channel blockers also act as vasodilators and are used as antiarrhythmics
As calcium channel blockers have a negative inotropic action they ______ heart contractility
As calcium channel blockers have a negative inotropic action, they decrease heart contractility
What are the 2 benefits of dilating the peripheral arteries using calcium channel blockers for animals with heart conditions (heart failure)?
- Reduces afterload
2. Allows peripheral blood flow and perfusion
What calcium channel blocker is used to treat congestive heart failure in cats?
Diltiazem
Name 2 possible side effects caused by calcium channel blockers
- Hypotension
2. Bradycardia
What is the main action of nitrate medicines?
Reduce preload
Vasodilators
Nitroglycerin is available as ______ preparations
Nitroglycerin is available as topical preparations
Which nitrate is subject to significant first pass metabolism?
Nitroglycerin
Nitroprusside is formulated as an _______ preparation
Nitroprusside is formulated as an injectable preparation
Which nitrate medicine should be administered at a continuous rate and requires close monitoring?
Nitroprusside
Isosorbide dinitrate is available as ____ formulations
Isosorbide dinitrate is available as oral formulations
Which nitrate is NOT allowed to be taken home?
Nitroprusside
Name 3 Phosphodiesterase inhibitors that are classified as vasodilators
- Sildenafil
- Tadalafil
- Pimobendan
Name 1 alpha 1 antagonist that has a vasodilator action
Prazosin
What is the main action of Class 1 antiarrhythmics?
Reduce maximal rate of depolarization
Name 2 class one antiarrhythmics
- Lidocaine
2. Quinidine
Class 1 antiarrhythmics are ___ channel blockers
Class 1 antiarrhythmics are sodium channel blockers
Class II antiarrhythmics are __-______ blockers
Class 2 antiarrhythmics are beta-adrenergic blockers
What is the main action of Class II antiarrhythmics?
Reduce sympathetic activity on the heart
Name 1 Class II antiarrhythmic
Atenolol
What is the main action of Class III antiarrhythmics?
Prolongs refractory period
Class III antiarrhythmics are ___ channel blockers
Class III antiarrhythmics are potassium channel blockers
Name one Class III antiarrhythmic
Sotalol
What is the action of Class IV antiarrhythmics?
decrease conduction through the AV node, and shorten phase two (the plateau) of the cardiac action potential.
Class IV antiarrhythmics are _____ channel blockers
Class IV are calcium channel blockers
Diltiazem belongs to which class if antiarrythmic?
Class IV
What is the gold standard +ve inotropic medicine used for dogs with congestive heart failure?
Pimobendan
Cats with congestive heart failure can be what 2 catecholamines?
Dopamine
Dobutamine
Catecholamines undergo extensive hepatic first pass metabolism so should not be given orally. True/False?
True - IV continuous infusion
