Lecture 20/21 - CHF Drugs Flashcards
1
Q
What major molecule controls the contractility of the heart?
A
Calcium
2
Q
What six aspects can be alter cardiac contractility?
A
Sensitivity to Ca Amount of Ca released from SR Amount stored in SR Amount of trigger Ca Na/Ca exchanger activity Intracellular Na concentration
3
Q
What are the four components of cardiac performance?
A
Preload
Afterload
Contractility
Heart rate
4
Q
What occurs in cardiogenic shock in regards to stroke work?
A
even with LV filling pressure increasing heart can’t counteract with increased work force
5
Q
What are the three aspects of pressure of fluid movement within the capillaries?
A
Hydrostatic
Colloid
Tissue
6
Q
What is normal transudation pressure?
A
10 to 15 mmHg
7
Q
Drug type that works on: Decreased CO
A
Positive inotropic drugs
8
Q
Drug type that works on: Na + Water retention
A
Diuretics
9
Q
Drug type that works on: RAA system
A
ACE inhibitors
10
Q
Drug type that works on: Cardiac remodeling
A
ACE inhibitors + B-blockers
11
Q
Drug type that works on: Congestion + Edema
A
Diuretics
12
Q
Drug type that works on: Increased venous volume + pressure
A
Vasodilators
13
Q
Drug type that works on: Increased afterload
A
Vasodilators
14
Q
What are the nine drug groups that can be used to treat CHF, or other cardiac conditions? (nine)
A
Diuretic ACE inhibitors Calcium sensitizers Digitalis Sympathomimetics Inodilators Beta blockers Alpha/Beta blockers Calcium channel blockers
15
Q
List the drugs: Diuretics
A
Furosemide
Spironolactone
Hydrochlortiazide
16
Q
List the drugs: ACE inhibitors
A
“-prils”
Enalapril
Benazepril
Captopril
17
Q
List the drugs: Calcium sensitizer
A
Pimobendan
18
Q
List the drugs: Digitalis
A
Digoxin
19
Q
List the drugs: Sympathomimetics
A
Dobutamine
Dopamine
20
Q
List the drugs: Inodilators
A
“-nones”
Amrinone
Milrinone
21
Q
List the drugs: Beta Blockers
A
“-olol”
Atenolol
Propranolol
Metoprolol
22
Q
List the drugs: A/B blockers
A
Carvedilol
23
Q
List the drugs: Calcium channel blockers
A
Diltiazem
24
Q
What characterizes CHF?
A
High cardiac filling pressure –>
Leading to venous congestion + Tissue fluid accumulation
25
Where, in regards to the CHF, does venous congestion occur?
Behind the affected side of the heart
26
What condition normally underlies CHF that can cause further progression of the disease?
Poor contractility
27
What can stimulate compensatory mechanisms to begin in CHF?
Chronic cardiac overload (Volume or Pressure)
28
What are the major signs of left-sided CHF?
Pulmonary venous congestion + edema
| Cough + Pulmonary crackles + etc.
29
What occurs with chronic pulmonary venous congestion?
Pulmonary hypertension
| Sometimes right sided CHF can begin
30
What are the major consequences of right-sided CHF?
Systemic venous hypertension
Jugular venous distension
Hepatic congestion + Pleural effusion
31
What are the three goals in the treatment of Acute CHF?
Decrease pulmonary edema
Increase CO
Oxygenate patient
32
What is acute CHF characterized by?
Severe cardiogenic pulmonary edema with poor CO
+/- pleural effusion
+/- abdominal effusion
33
What changes with chronic CHF even with medical management?
Even with drugs on board
| Will still see pleural effusion + ascites
34
What is a very important medication in Chronic heart failure for support of myocardial function?
Pimobendan
35
What can be given with Pimobendan if CHF is severe?
Digoxin
36
What are two examples of diastolic dysfunction?
Hypertrophic cardiomyopathy
-- and --
Cardiac tamponade
37
What is the treatment for cardiac tamponade?
Pericardiocentesis - to relive the pressure on the heart and allow it to fill normally
No medical management
38
What specific animal tends to suffer from hypertrophic cardiomyopathy the most?
Maine Coon Cats
39
What does hypertrophic cardiomyopathy impair in the heart?
Ventricular filling
40
What is a major overall goal when treating hypertrophic cardiomyopathy?
Slow the heart rate - allows for increased filling time + reduces occurance of ischemia
41
What is a goal of a drug used to treat hypertrophic cardiomyopathy?
Improve cardiac relaxation
42
What medications are most helpful when treating hypertrophic cardiomyopathy?
Furosemide
-- and --
ACEi
43
When would you most use furosemide in treating hypertrophic cardiomyopathy?
When CHF begins to develop
44
Why are diuretics used to treat CHF?
Control edema + effusion
45
Describe: Furosemide
Loop-diruetic
| Used mostly in cases of cardiogenic edema/effusion
46
What are the recommendations for Furosemide use in chronic HF?
not used as monotherapy
47
What is Furosemide used for in regards to acute CHF?
Sudden onset pulmonary edema
48
What is the primary use of Furosemide in racing horses?
Excercise induced pulmonary hemorrhage
49
What is an adverse effect of Furosemide?
Excessive fluid and/or electrolyte loss
50
Describe: Spironolactone
K-sparing diuretic, little effect in dogs though
51
What are the adverse effects of Spironolactone?
Excess K retention + GI disturbances
52
What are contrindicated uses of Spironolactone?
Hyperkalemic patients
| Patients on ACEi + K supplements
53
What specific disease processes is Spironolactone used for?
Chronic refractory HF
54
When is a thiazide diuretic used?
In dogs that have become resistant to furosemide
55
What is occurring biochemically with ACEi?
Inhibits ACE
| Decreasing ANGII + Increase Bradykinin
56
Why does bradykinin increase with ACEi?
ACE normally degrades Bradykinin
57
What is a contraindication for ACEi? Why?
Liver insuffiency, ACEi are pro-drugs and need to be metabolized by the liver
58
What are the main benefits of ACEi use?
Reduce neurohormonal activation
-- and --
Art/Venous vasodilation
MAY stop abnormal CV remodeling changes
59
What type of diuretic effect does ACEi have?
Renal Na retention
60
What are the specific therapeutic uses of ACEi?
Chronic management of CHF
Dilated cardiomyopathy
Valvular insufficiency
Hypertrophic cardiomyopathy
61
What disease is ACEi the first drug of choice to treat?
Dogs: Systemic arterial hypertension
62
What adverse effects are seen in ACEi use?
Hypotension + GI upset + Hyperkalemia
63
What happens to treatment regimine if azotemia develops?
Diuretic dose decreased first!
| then ACEi is reduced or removed
64
Characteristics: Enalapril
most excreted in kidney
| 2hr half life
65
Characteristics: Benazepril
Much longer 1/2 in cats (up to a day)
| Renal + Hepatic excretion
66
What is pimobendan?
Inotropic drug + Vasodilating properties
67
How does pimpbendan work?
Inhibits phosphodiesterase III = vasodilation
Increase cAMP = Increase L Ca2+ channels
Increase myofiliament sensitivity to Ca
68
What is the therapeutic use for Pimobendan?
CHF --
Dilated cardiomyopathy
Chronic mitral valve disease
69
Pharmokinetics: Pimobendan
>90% protein bound
Excretion through feces
Delay from peak concentration + maximal effect
70
What are the adverse effects of pimobendan?
not many lethargy, diarrhea, dyspnea
| Rare: Azotemia
71
What do glycocides contain?
Aglycon
| Three digitoxose
72
What plant contains glycosides?
Foxglove
73
What is the main function of Digoxin?
Positive iontropic effect
74
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
75
What does digoxin have anti-arrhythmic effects towardS?
Supraventicular tachyarrhythmia
76
By what mechanisms does digoxin have anti-arrhythmic effects?
Improves arterial baroreceptor sensitivity
| Increased vagal activity
77
What is the primary use for Digoxin when wanted for its anti-arrhythmic effects?
Artrial fibrillations - Dilated cardiomyopathy or MVD
78
What is a contrindiation for digoxin usage?
Cats with hypertrophic cardiomyopathy
79
Why do you see increased serum levels of digoxin with dog and cats that have renal problems?
Reduced body clearance
-- and --
Volume of distribution
80
What does Digoxin bind to mostly in the body? Why is this a problem?
Skeletal muscle
| -- if animal has wasting, decreased effect of the drug
81
What is the treatment for digoxin toxicity?
Intravenous K
Lidocaine + Propranolol + Phenytonin
Immunotherapy
82
What is the biggest adverse effect of Digoxin?
Cardiac toxicity
83
What are some arrhythmias that Digoxin stimulate?
Sinus bradycardia
Ectopic ventricular beats
AV block
84
What is the most common arrhythmia due to Digoxin that can cause death?
Ventricular fibrillation
85
What causes a decrease in digoxin absorbtion?
Antacids
Kaolin-pectin
Food
86
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
87
What is the main method of excretion of Digoxin?
renal
88
How is Digoxin transported?
Pgp
89
What seven things can increase digialis toxicity?
```
Hypokalemia
B-antagonist
Calcium channel blockers
Decrease plasma protein
Decrease renal excretion
Altered GI flora
Sensitizing myocardium
```
90
What are the two ways K interacts with digitalis?
Inhibit each other binding to Na/K ATPase receptor
-- and --
K reduces cardiac automaticity
91
What other compound decreases digitalis toxicity?
Mg
92
What compound SHOULD NOT BE GIVEN with digitalis?
Calcium
93
What is the standard drug therapy for heart failure?
Diuretics
ACEi
Pimobendan
94
What breaks down cAMP?
PDE
95
What does cAMP phosphorylate?
PKA + CREB
96
What creates cAMP, what does it make it from?
Adenylyl cyclase
| Uses ATP
97
Drug for goal of therapy: Reduced preload
Diuretic
-- and --
Venodilator
98
Drug for goal of therapy: Reduced afterload
Arteriodilator
99
Drug for goal of therapy: Increased contractility
Inotropic drug
100
Drug for goal of therapy: Reduced energy expenditure
B-adrenergic antagonist
101
What CHF effect causes the need for reduced preload?
Increased BV + Venous tone
102
What CHF effect causes the need for reduced afterload?
Increased Aortic impedance + Arterial contriction
103
What CHF effect causes the need for increased contractility?
Ventricular dilation + Reduced pumping force
104
What CHF effect causes the need for reduced energy expenditure?
Increase HR due to reflex tachycardia via SNS hyperactivity
105
What drug group can be used to slow HR and reduce myocardial O2 comsumption?
B-blocker
106
What do calcium entry blockers do to the heart?
Coronary + Systemic vasodilation
| Enhanced myocardial relaxation
107
What is a good use for a calcium entry blocker, what drug?
Diltiazem
| Hypertrophic cardiomyopathy
108
What is contraindicated with diltiazem?
B-blockers
109
What are important myocardial protective agents?
Some B-blocker s
| Carvedilol + Metoprolol
110
When do you need myocardial protective agents?
Dilated cardiomyopathy
-- and --
Chronic valve disease
111
How do the inodilators, Amrinone + Milrinone, work?
Inhibit phosphodiesterase III
112
What effects do Amrinone + Milrinone have?
Increase myocardial contractility
-- and --
Vasodilation
113
What are adverse effects of Amrinone + Milrinone?
Worsen ventricular tachyarrhythmias
| Reflex tachycardia
114
Which, Amrinone or Milrinone, last the longest?
Amrinone
