Ionotropic Drugs: Limitations in Heart Failure Flashcards Preview

Cardiovascular Unit 1 > Ionotropic Drugs: Limitations in Heart Failure > Flashcards

Flashcards in Ionotropic Drugs: Limitations in Heart Failure Deck (24):
1

What does digoxin do?

decrease chronotropy/ increase ionotropy (weak)

1. ^ baroreceptor activity > blocks NE > shuts off sympathetic system >> decreased HR
2. Blocks Na/ K ATPase > increase intracellular Na > less Ca exchanged out of cell >> more Ca

2

How is digoxin excreted?

Renally
-careful with patients with renal dysfxn
-long half life - 7 days to steady state!
-metabolism = P-glycoprotein

3

It's important to monitor digoxin, what serum levels are desired (and don't kill patient)?

.5 - 1 ng/ml

4

Who would you give digoxin to?

-Patients with HFrEF, who aren't responding well to treatment with ACEI/ ARBs, Beta blockers, diuretics
-All patients with sever HF symptoms
-No benefit in HFpEF!

5

When do you check digoxin serum levels?

7 - 14 days after starting therapy

6

What are the toxicities with digoxin?

-Heart block, bradycardia, arrythmia
-GI upset
-seeing blue/ green halos
-hyperkalemia
-confusion

7

How does taking antiarrythmics affect your digoxin dosing?

They inhibit P-gp
-you should reduce digoxin dose by 50%

8

What other medications can adversely affect digoxin levels?

-Azole antifungals
-Calcium channel blockers (verapamil)
-Macrolides
-quinine

*inhibitors of P-gp
Induces: rifampin, St. John's Wort

9

What effects do potassium, calcium, and magnesium have on digitoxin toxicity?

Toxicity from:
-hypercalcemia
-hypokalemia
-hypomagnesemia

10

What medication can you give in the ER to someone who has digoxin toxicity?

Digoxin immune fab (ovine)

11

What happens if you stop digoxin treatment instantly?

Exercise intolerance

12

T/F: Digoxin reduces mortality

False- only reduces hospitalization

13

Name the two big inotrope medications

Dobutamine
Milrinone

14

What patients generally get inotropic medicine?

Class III - "cold and dry" (hypoperfusion)
Class IV - "cold and wet" (hypoperfusion and congestion)

15

Contrast the biochemical mechanism of action of milrinone and dobutamine?

Milrinone: inhibits PDE > accumulation of Ca
Dobutamine: B1 agonist to stimulate G proteins > increase Ca

16

With each of the following, does milrinone or dobutamine have a stronger effect?
1) vasodilation
2) enhanced inotropy
3) increased heart rate
4) tacchyarrythmia

Dobutamine:
enhanced inotropy
increased HR
tacchyarrythmia

milrinone:
vasodilation

17

Are inotropes for short-term or long-term use?

Short term

18

Which inotrope has a shorter half life?

=Dobutamine: 2 minutes
-more rapid onset/ clearing

Milrinone: 1- 3 hours
-cleared by kidneys

19

If you have a hypotensive patient, which inotrope would be better?

Dobutamine
*milrinone has more moderate vasodilation

20

If your patient is taking beta blockers, which inotrope would you use?

Milrinone
*dobutamine is a beta agonist

21

According to the Heart Failure Society of America, when should you consider giving inotropes?

-Patients with advanced HF and low output syndrome
-patients have marginal BP ( to relieve symptoms and improve end-organ function

**NOT LONG TERM
**MAKES THEM FEEL BETTER, BUT NO BETTER OUTCOMES

22

Side effects of both?

Milrinone: HYPOTENSION, thrombocytopenia, tachycardia, arrythmia

Dobutamine: Angina, tachyarrythmia

23

Alright Dopamine is also an inotrope, but we didn't talk about it much. How does it work?

Norepinephrine precursor > stimulates adrenergic receptors

24

Dopamine has dose dependent effects. Explain the effects at low, moderate, and high doses?

RIP:
Renal - low dose > dopaminergic
Inotrope - moderate dose > beta receptors
Pressor - high dose > alpha receptor