Positive Inotropic Drugs in Heart Failure - Ch. 51 Flashcards

1
Q

What is Heart failure?

A

The heart is unable to pump enough blood to meet the body’s metabolic needs

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2
Q

What do heart failure symptoms depend on?

A

Cardiac area affected
- left ventricular failure
-Right ventricular failure

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3
Q

What are Inotropic drugs?

A

Drugs that increase the force of myocardiac contraction

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4
Q

What are inotropic drugs used for?

A

Treatment of heart failure

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5
Q

What are the kinds of Inotropic drugs?

A

Cardiac glycosides
Sympathomimetic drugs
Phosphodiesterase inhibitors

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6
Q

Example of cardiac glycoside?

A

Digoxin

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7
Q

Examples of Sympathomimetic drugs?

A

Dobutamine
Dopamine

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8
Q

What are some other drugs used in heart failure?

A

Diuretics (K losing)
Beta-adrenoceptor antagonists
RAAS drugs (ACEIS, ARBs, Aldosterone antagonists)
Vasodilators (hrydralazine)
Organic nitrates (isosorbide dinitrate, nitroglycerin)

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9
Q

What causes heart failure to occur?

A

Cardiac muscle defect
Supraventricular dysrhythmias
Other defects beyond cardiac muscle

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10
Q

What cardiac muscle defects cause HF?

A

MI
Congenital

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11
Q

What Supraventricular dysrhythmias cause HF?

A

Atrial fibrillation
Atrial flutter

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12
Q

What other defects beyond cardiac muscle cause HF?

A

Coronary artery disease -ischemia
Hypertension/pulmonary hypertension
valve deficiency
Diabetes mellitus

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13
Q

What are the outcomes of HF?

A

Structural changes in cardiac muscle/connective tissue in ventricular wall

Functional changes in the ability of the ventricle to pump blood

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14
Q

What are symptoms of heart failure?

A

Reflex tachycardia
Edema
Elevated venous pressure
Dyspnea
Weakness
Cardiomegaly

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15
Q

What are inotropic drug effects on cardiac muscle?

A

Positive or negative force of muscualr contractions

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16
Q

What are chronotropic drug effects on cardiac muscle?

A

Positive or negative rate of the heartbeat

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17
Q

What are the dromotropic drug effects on cardiac muscle?

A

Positive or negative conduction speed of electrical impulses

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18
Q

Where were cardiac glycosides (digoxin) originally obtained from?

A

Digitalis plant (foxglove)

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19
Q

What are 3 S’s of Digoxin action?

A

Strengthens
Slows
Slows

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20
Q

What is β€œstrengthens” in digoxin action?

A

Positive inotropic effect
-increase in force of myocardiac contraction

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21
Q

What is the 1st β€œSlows” in digoxin action?

A

Negative chronotropic effect
-reduced heart rate at SA node

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22
Q

What is the 2nd β€œSlows” in digoxin action?

A

Negative dromotropic effect
-Decreases AV nodal conduction

23
Q

What are the effects of digoxin?

A

↑stroke volume and cardiac output
↓ venous BP and vein engorgment
↑ coronary circulation
Promote diuresis (due to improve kidney perfusion)
Palliation of exertional, paroxysmal and
nocturnal dyspnea, cough, and cyanosis

24
Q

What is digoxin used for?

A

Heart failure
Supraventricular dysrhythmias (Afib and flutter)

25
Q

How is Digoxin supplied?

A

0.25mg, 0.125mg, 0.0625 mg/tablet

26
Q

What adverse effects are associated with Digoxin?

A

Narrow therapeutic window
Low potassium and Mg levels increase toxcity
Generalized malaise
GI disturbances
Colored vision
CV effects

27
Q

What is the narrow therapeutic index of digoxin?

A

Toxicity is slightly above therapeutic plasma level
-drugs leves must be monitored

28
Q

What is generalized malaise?

A

β€œjust don’t feel right”
Fatigue, weakness, confusion

29
Q

What GI disturbanced are caused by digoxin?

A

Anorexia, nausea, vomiting, diarrhea

30
Q

What is colored vision?

A

Seeing yellow, green, purple, halo vision, flickering lights

31
Q

What CV adverse effects are caused by digoxin?

A

Dysrythmias including bradycardia

32
Q

What must you take to monitor for CV adverse effects associated with digoxin?

A

Take apical pulse
-Minimum 60bpm

33
Q

What is digoxin toxicity?

A

Common medication problem,can be life threatning
Accidental or intention overdose
Change in renal function (decreased elimination)
Diarrhea episodes

-Reduce or stop dosing

34
Q

What is Digoxin immune Fab (Digibind) therapy

A

Used as an antidote to rapidly reduce digoxin toxcity

35
Q

How does Digoxin immune Fab (Digibind) therapy work?

A

Binds to digoxin to stop life-threatning cardiac dysrythmias

36
Q

What factors increase risk of digoxin toxicity?

A

Low K (e.g, Furosemide loop diuretic)
High Calcium
Low magnesium
Renal dysfunction
Elderly
Hypothyroid
Herbal products
Drugs

37
Q

What herbal products increase risk of digoxin toxicity?

A

Ginkgo
St. Johns Wort

38
Q

What ways do drugs increase risk of digoxin toxicity?

A

Lead to hypokalemia then toxicity
Increase absorption of digoxin
Decreases renal clearance of digoxin (Plasma x2)

39
Q

What drugs lead to hypokalemia then to digoxin toxicity?

A

Amphotericin B, furosemide, thiazides, laxatives,
steroids

40
Q

What drugs Increase absorption of digoxin and cause digoxin toxicity?

A

anticholinergics

41
Q

What drugs decrease renal clearance of digoxin and lead to digoxin toxicity?

A

Quinidine
Verapamil

42
Q

What serum labs need to be assessed for a client on digoxin?

A

Potassium
Sodium
Magnesium
Calsium
Renal and liver function studies

43
Q

What should the apical pulse (not radial) of someone on digoxin be?

A

<60 or >120 bpm
-less than 90 in an infant
-Slow rate= sign of toxicity

44
Q

What signs/symptoms indicate digoxin toxicity? Notify HCP, Hold dose!!!

A

Anorexia
Nausea
Vomitting
Diarrhea
Visual disturbances: Blurred vision, seeing green or yellow halos around bjects

45
Q

What is the only way sympathomimetic drugs are administered?

A

IV infusion only

46
Q

What do sympathomimetic drugs do?

A

Activate Beta1-adrenoceptors
-Increase cardiac contractility

47
Q

What are sympathomimetic drugs used for?

A

Only in severe or acute HF

48
Q

What do Phosphodiesterase Inhibitors do?

A

Inhibit the enzyme Phosphodiesterase and produce a positve inotropic respone amd positive lusitropic effect

49
Q

What are two phosphodiesterase inhibitor agents?

A

Milrinone
amrinone

50
Q

What are Phosphodiesterase Inhibitors used for?

A

Short-term management of HF

51
Q

When are Phosphodiesterase Inhibitors given?

A

When client has not responded to digoxin, diuretics and/or vasodilators

52
Q

How are Phosphodiesterase Inhibitors administered?

A

Weekly 6-hour IV infusions

53
Q

What theraputic effects should be monitored when a client is given a positive inotropic agent?

A

Increased urinary output (adequate fluids important)
Decreased edema, shortness of breath (dyspnea), rales (crackles), and fatigue
Resolvinf of paroxysmal nocturnal dyspnea
Improved peripheral pulses, skin colour and temperature