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Flashcards in Drug treatment for CHF Deck (33)
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1
Q

What are the 6 mechanisms of low cardiac output?

A

1) Low preload
2) HR too slow
3) HR too fast
4) Diminished inotropic state (contractility)
5) Excessive vasoconstriction
6) Excessive or abnormal contractility

2
Q

What is the treatment for low preload leading to low CO?

A

Crystalloid, blood

3
Q

What is the treatment for bradycardia leading to low CO?

A

Atropine, isoproterenol, pacemaker

4
Q

What is the treatment for tachycardia, which leads to low CO?

A

Cardioversion, antiarrhythmic drugs

5
Q

What is the treatment for diminished inotropic state (contractility), leading to low CO?

A

Epi, dopamine, dobutamine, (amrinone), calcium, glucagon, digoxin

6
Q

What is the treatment for excessive vasoconstriction, leading to low CO?

A

Lisinopril, hydralazine, prazosin, carvedilol, nitroglycerin, nitroprusside

7
Q

What is the treatment for excessive or abnormal contractility leading to low CO?

A

Metoprolol, verapamil

8
Q

What is atropine (sulfate)?

A

Atropine is a competitive muscarinic acetylcholine receptor antagonist. It is a naturally occurring tropane alkaloid extracted from deadly nightshade, Jimson weed, and other plants of the family Solanaceae.

Atropine dilates the pupils, increases heart rate, and reduces salivation and other secretions.

9
Q

To what drug class does atropine belong?

A

Pharmacologic class => muscarinic receptor antagonist, belladonna alkaloid

Therapeutic class—antiarrhythmic, vagolytic, mydriatic

10
Q

Describe the pharmacodynamics of atropine.

A
  • Blocks the effects of ACh on the SA and AV nodes
    => increases conduction and HR
    = > decreases secretions in various glands (e.g. salivary, bronchial, sweat)
11
Q

Describe the pharmacokinetics of atropine.

A
  • Given IV, endotracheally, and topically (in the eye)
12
Q

What toxicity is associated with atropine?

A
  • Avoid in patients with glaucoma.

- Also avoid in obstructive uropathy, GI obstruction, ileus, toxic megacolon

13
Q

What special considerations should be noted in patients on atropine?

A
  • Can cause agitation, confusion (especially in the elderly), delirium, disorientation
  • Blurred vision
  • Constipation
  • Urine retention
  • Watch out especially in older men with BPH
14
Q

What is the dose/route for atropine?

A
  • Indication: symptomatic bradycardia
  • Give 0.5 to 1 mg IV push, may repeat
  • Given pre-op to reduce secretions and to block cardiac vagal reflexes, give 0.4 mg IM one hour before anesthesia
15
Q

To what drug class does dopamine (Intropin™) belong?

A

Pharmacologic : adrenergic and dopaminergic receptor agonist

Therapeutic class: inotropic agent; vasopressor

16
Q

Describe the pharmacodynamics of dopamine.

A
  • Stimulates dopamine receptors
    • increases renal blood flow
    • beta-1, and alpha-1 receptors at different infusion rates
17
Q

Describe the pharmacokinetics of dopamine.

A
  • Can only be infused IV
  • Acts quickly within minutes
  • Half-life brief (minutes), hence continuous infusion
18
Q

What toxicity is associated with dopamine?

A
  • Ectopy, tachycardia, angina, nausea, peripheral gangrene (excess vasoconstriction)
  • Extravasation
19
Q

What special conditions should be considered in patients on dopamine?

A
  • Correct hypovolemia first
  • Administer through large vein
  • Prevent extravasation
  • Monitor patient closely
20
Q

What is the indication/dose/route of dopamine?

A

Indication: shock, CHF
Dose: 1 mcg/kg/min up to 30 mcg/kg/min
- low 1-2, moderate 2-10, high 10-30 mcg/kg/min

21
Q

What is Dobutamine (Dobutrex™)?

A

Dobutamine is a sympathomimetic drug used in the treatment of heart failure and cardiogenic shock.

Its primary mechanism is direct stimulation of β1 receptors of the sympathetic nervous system.

22
Q

To what class does dobutamine belong?

A

Pharmacologic: adrenergic receptor agonist

Therapeutic: positive inotropic agent

23
Q

Describe the pharmacodynamics of dobutamine.

A
  • Selectively stimulates beta-1 adrenergic receptors to increase contractility and SV resulting in increased cardiac output
  • HR usually remains unchanged
24
Q

Describe the pharmacokinetics of dobutamine.

A
  • Can only be infused IV
  • Acts quickly within minutes
  • Half-life brief (minutes) => continuous infusion
25
Q

What toxicity is associated with dobutamine?

A
  • Ectopy, PVC’s, tachycardia, hypertension, hypotension
26
Q

What special conditions should be noted in patients on dobutamine?

A
  • Correct hypovolemia first

- Monitor patient closely

27
Q

What are the indications/dose/route for dobutamine?

A
  • 2.5-10 mcg/kg/min

- Rarely doses up to 40 mcg/kg/min may be needed

28
Q

What is epinephrine best used for?

A
  • Anaphylactic shock
  • Cardiac arrest with asystole or fine VF
  • After open heart surgery as patient is “warming up”
29
Q

What is the best use/indication for lisinopril (vasodilator)?

A
  • Afterload reduction
  • Reduces excessive SVR
  • Increases CO
30
Q

Why is hydralazine not used by itself (vasodilator)?

A
  • Not useful by itself because of reflex fluid retention and tachycarida
31
Q

What is Bidil?

A

Bidil is a vasodilator made of hydralazine plus isosorbide dinitrate.

  • It is very effective in African American patients more so than patients of other backgrounds
32
Q

In what situation is nitroprusside used?

A

Nitroprusside is generally used in an ICU or coronary care unit because it must be given via IV.

  • it is useful in reducing afterload
33
Q

What agents reduce preload?

A
  • Loop diuretics
    - Powerful diuretic, acts on the loop of Henle, available po or iv
  • Thiazide diuretics
    - Po only and less effective
  • Aldosterone antagonist diuretics
    - Po only and can cause K retention