Flashcards in Lecture 20/21 - CHF Drugs Deck (114):
What major molecule controls the contractility of the heart?
What six aspects can be alter cardiac contractility?
Sensitivity to Ca
Amount of Ca released from SR
Amount stored in SR
Amount of trigger Ca
Na/Ca exchanger activity
Intracellular Na concentration
What are the four components of cardiac performance?
What occurs in cardiogenic shock in regards to stroke work?
even with LV filling pressure increasing heart can't counteract with increased work force
What are the three aspects of pressure of fluid movement within the capillaries?
What is normal transudation pressure?
10 to 15 mmHg
Drug type that works on: Decreased CO
Positive inotropic drugs
Drug type that works on: Na + Water retention
Drug type that works on: RAA system
Drug type that works on: Cardiac remodeling
ACE inhibitors + B-blockers
Drug type that works on: Congestion + Edema
Drug type that works on: Increased venous volume + pressure
Drug type that works on: Increased afterload
What are the nine drug groups that can be used to treat CHF, or other cardiac conditions? (nine)
Calcium channel blockers
List the drugs: Diuretics
List the drugs: ACE inhibitors
List the drugs: Calcium sensitizer
List the drugs: Digitalis
List the drugs: Sympathomimetics
List the drugs: Inodilators
List the drugs: Beta Blockers
List the drugs: A/B blockers
List the drugs: Calcium channel blockers
What characterizes CHF?
High cardiac filling pressure -->
Leading to venous congestion + Tissue fluid accumulation
Where, in regards to the CHF, does venous congestion occur?
Behind the affected side of the heart
What condition normally underlies CHF that can cause further progression of the disease?
What can stimulate compensatory mechanisms to begin in CHF?
Chronic cardiac overload (Volume or Pressure)
What are the major signs of left-sided CHF?
Pulmonary venous congestion + edema
Cough + Pulmonary crackles + etc.
What occurs with chronic pulmonary venous congestion?
Sometimes right sided CHF can begin
What are the major consequences of right-sided CHF?
Systemic venous hypertension
Jugular venous distension
Hepatic congestion + Pleural effusion
What are the three goals in the treatment of Acute CHF?
Decrease pulmonary edema
What is acute CHF characterized by?
Severe cardiogenic pulmonary edema with poor CO
+/- pleural effusion
+/- abdominal effusion
What changes with chronic CHF even with medical management?
Even with drugs on board
Will still see pleural effusion + ascites
What is a very important medication in Chronic heart failure for support of myocardial function?
What can be given with Pimobendan if CHF is severe?
What are two examples of diastolic dysfunction?
-- and --
What is the treatment for cardiac tamponade?
Pericardiocentesis - to relive the pressure on the heart and allow it to fill normally
No medical management
What specific animal tends to suffer from hypertrophic cardiomyopathy the most?
Maine Coon Cats
What does hypertrophic cardiomyopathy impair in the heart?
What is a major overall goal when treating hypertrophic cardiomyopathy?
Slow the heart rate - allows for increased filling time + reduces occurance of ischemia
What is a goal of a drug used to treat hypertrophic cardiomyopathy?
Improve cardiac relaxation
What medications are most helpful when treating hypertrophic cardiomyopathy?
-- and --
When would you most use furosemide in treating hypertrophic cardiomyopathy?
When CHF begins to develop
Why are diuretics used to treat CHF?
Control edema + effusion
Used mostly in cases of cardiogenic edema/effusion
What are the recommendations for Furosemide use in chronic HF?
not used as monotherapy
What is Furosemide used for in regards to acute CHF?
Sudden onset pulmonary edema
What is the primary use of Furosemide in racing horses?
Excercise induced pulmonary hemorrhage
What is an adverse effect of Furosemide?
Excessive fluid and/or electrolyte loss
K-sparing diuretic, little effect in dogs though
What are the adverse effects of Spironolactone?
Excess K retention + GI disturbances
What are contrindicated uses of Spironolactone?
Patients on ACEi + K supplements
What specific disease processes is Spironolactone used for?
Chronic refractory HF
When is a thiazide diuretic used?
In dogs that have become resistant to furosemide
What is occurring biochemically with ACEi?
Decreasing ANGII + Increase Bradykinin
Why does bradykinin increase with ACEi?
ACE normally degrades Bradykinin
What is a contraindication for ACEi? Why?
Liver insuffiency, ACEi are pro-drugs and need to be metabolized by the liver
What are the main benefits of ACEi use?
Reduce neurohormonal activation
-- and --
MAY stop abnormal CV remodeling changes
What type of diuretic effect does ACEi have?
Renal Na retention
What are the specific therapeutic uses of ACEi?
Chronic management of CHF
What disease is ACEi the first drug of choice to treat?
Dogs: Systemic arterial hypertension
What adverse effects are seen in ACEi use?
Hypotension + GI upset + Hyperkalemia
What happens to treatment regimine if azotemia develops?
Diuretic dose decreased first!
then ACEi is reduced or removed
most excreted in kidney
2hr half life
Much longer 1/2 in cats (up to a day)
Renal + Hepatic excretion
What is pimobendan?
Inotropic drug + Vasodilating properties
How does pimpbendan work?
Inhibits phosphodiesterase III = vasodilation
Increase cAMP = Increase L Ca2+ channels
Increase myofiliament sensitivity to Ca
What is the therapeutic use for Pimobendan?
Chronic mitral valve disease
>90% protein bound
Excretion through feces
Delay from peak concentration + maximal effect
What are the adverse effects of pimobendan?
not many lethargy, diarrhea, dyspnea
What do glycocides contain?
What plant contains glycosides?
What is the main function of Digoxin?
Positive iontropic effect
What is the mechanism of action for digoxin?
Bind to Na/K ATPase channel on myocardial membrane
Decrease Na transport leading to increased intracellular Ca
What does digoxin have anti-arrhythmic effects towardS?
By what mechanisms does digoxin have anti-arrhythmic effects?
Improves arterial baroreceptor sensitivity
Increased vagal activity
What is the primary use for Digoxin when wanted for its anti-arrhythmic effects?
Artrial fibrillations - Dilated cardiomyopathy or MVD
What is a contrindiation for digoxin usage?
Cats with hypertrophic cardiomyopathy
Why do you see increased serum levels of digoxin with dog and cats that have renal problems?
Reduced body clearance
-- and --
Volume of distribution
What does Digoxin bind to mostly in the body? Why is this a problem?
-- if animal has wasting, decreased effect of the drug
What is the treatment for digoxin toxicity?
Lidocaine + Propranolol + Phenytonin
What is the biggest adverse effect of Digoxin?
What are some arrhythmias that Digoxin stimulate?
Ectopic ventricular beats
What is the most common arrhythmia due to Digoxin that can cause death?
What causes a decrease in digoxin absorbtion?
How long does it take for Digoxin to reach SS in the blood of: Horse, Dog, and Cat
Horse - 3 days ~
Dog - 7 days
Cat - 10 days
What is the main method of excretion of Digoxin?
How is Digoxin transported?
What seven things can increase digialis toxicity?
Calcium channel blockers
Decrease plasma protein
Decrease renal excretion
Altered GI flora
What are the two ways K interacts with digitalis?
Inhibit each other binding to Na/K ATPase receptor
-- and --
K reduces cardiac automaticity
What other compound decreases digitalis toxicity?
What compound SHOULD NOT BE GIVEN with digitalis?
What is the standard drug therapy for heart failure?
What breaks down cAMP?
What does cAMP phosphorylate?
PKA + CREB
What creates cAMP, what does it make it from?
Drug for goal of therapy: Reduced preload
-- and --
Drug for goal of therapy: Reduced afterload
Drug for goal of therapy: Increased contractility
Drug for goal of therapy: Reduced energy expenditure
What CHF effect causes the need for reduced preload?
Increased BV + Venous tone
What CHF effect causes the need for reduced afterload?
Increased Aortic impedance + Arterial contriction
What CHF effect causes the need for increased contractility?
Ventricular dilation + Reduced pumping force
What CHF effect causes the need for reduced energy expenditure?
Increase HR due to reflex tachycardia via SNS hyperactivity
What drug group can be used to slow HR and reduce myocardial O2 comsumption?
What do calcium entry blockers do to the heart?
Coronary + Systemic vasodilation
Enhanced myocardial relaxation
What is a good use for a calcium entry blocker, what drug?
What is contraindicated with diltiazem?
What are important myocardial protective agents?
Some B-blocker s
Carvedilol + Metoprolol
When do you need myocardial protective agents?
-- and --
Chronic valve disease
How do the inodilators, Amrinone + Milrinone, work?
Inhibit phosphodiesterase III
What effects do Amrinone + Milrinone have?
Increase myocardial contractility
-- and --
What are adverse effects of Amrinone + Milrinone?
Worsen ventricular tachyarrhythmias