20. Inotropic Drugs-Limitations in Heart Failure Flashcards
Why does hypocalcemia cause dig tox?
dig enhances Ca++ absorption by myocytes (that’s the point, but don’t overdo it)
Digoxin can also bind in the ____ and ____ of the heart to slow the HR and treat A-fib.
SA node; AV node
What is dobutamine?
inotropic drug
What are the s/s of dig tox?
- GI: upset/pain/vomiting**** 2. neuro: weakness, confusion 3. hyperkalemia 4. cardiac: bradycardia, heart block, arrhythmias 5. visual: sensitivity to light, yellow halos, blurred vision
With increased plasma NE, there is an increased risk of _____ in HF pts.
death
_____ increases PNS activity by activating baroreceptors in the carotids and the AA.
Digoxin
What is milrinone?
an ionotropic drug
_____ are like a protective shield for the heart in overproduction of NE.
Beta-blockers
What is the half life of digoxin?
38 hours (7-10 days to steady state)
The diuretics end in -____.
ide
How does digoxin increase parasympathetic activity?
by increasing baroreceptor sensitivity in the carotids and the AA
How does milrinone work?
it inhibits phosphodiesterase (PDE) to increase force of contraction and also causes vasodilation
If your pt has a life-threatening dig tox or OD, give _____.
digoxine immune Ab
_____ can also bind in the SA and AV node of the heart to slow the HR and treat A-fib.
Digoxin
What is the problem with the inotropes?
they can be pro-arrhythmic
____ is an inotrope that blocks the Na+/Ca++ ATPase.
Digoxin
Beta-blockers have been shown to reduce morbidity and mortality and is recommended for all ______ pts unless contraindicated.
HFrEF
What is dopamine?
a precursor of NE; benefits = RIP (renal, inotropic, and pressor effects depending on dose)
You would not give _____ to someone already taking a beta-blocker.
dobutamine
Beta-blockers improve the overall ____ of the heart and decrease mortality over time.
ejection fraction
Digoxin is an inotrope that blocks the Na+/Ca++ ATPase, causing ____ to accumulate on the ____ side.
Na+; intracellular
Why does hypomagnesemia cause dig tox?
can sensitize the heart to dig-induced arrhythmias
Digoxin reduces _____ but does not impact mortality.
hospitalization
Which has the shorter half life: milrinone or dobutamine?
dobutamine
Is BMP production good or bad in heart failure? What does BNP do?
GOOD! It’s protective: causes vasodilation, lowers BP, reduces symp tone, reduces aldosterone, and causes naturesis/diuresis
What electrolytes can cause dig toxicity when low?
- K+ 2. Ca++ 3. Mg++
Digoxin is an inotrope that blocks the _____ channel.
Na+/Ca++ ATPase
Beta-blockers end in -____.
olol
Why does hypokalemia cause dig tox?
it causes increased dig binding, increasing its effects, bc it binds to the same receptor as K+
How does dobutamine work?
binds to the beta-1 receptor to increase cAMP and increase intracellular Ca++ to increase inotropy
Digoxin has a very _____ therapeutic window.
narrow
HFpEF is _____ dysfunction.
diastolic
Overstimulation of the Beta-1 receptor can cause ____.
myocyte toxicity and cell death; increased arrhythmias
Who are inotropes given to?
pts with advanced HF and low output syndrome
When is digoxin given?
- to HFrEF pts 2. A-fib 3. cardiomegaly
Digoxin is an _____ that blocks the Na+/Ca++ ATPase.
inotrope
Digoxin in ____ excreted.
renally
Digoxin can also bind in the SA and AV node of the heart to ____ and treat ____.
slow the HR; A-fib
