Drugs for CHF Flashcards
If you’re Stage A for CHF what does that mean and what measures do you take to prevent it?
You’re AT RISK.
Lifestyle changes: Manage HTN, lipids, diabetes. No smoking or alcohol.
Preventative Drugs: ACE inhibitors (Captopril… any pril)
Stage B CHF means what? What drug class do you add to your ACE inhibitor at this point?
Stabe B CHF means your EF has dropped below 50%
Keep taking your ACE inhibitor, and add a B-blocker to decrease the workload on your heart.
Stage C CHF is indicated by what? What do you take now?
Significant onset of symptoms indicates a Stage C CHF patient.
Edema, Dyspnea, Orthopnea, PND.
Take your ACE inhibitor, your B-blocker, and add a diuretic, Digoxin, and Spironolactone.
WTF is spironolactone?
A K+ sparing diuretic. (Makes you secrete water but retain your body’s potassium content)
It’s a direct Aldosterone antagonist.
What is the treatment when you reach Stage D Heart Failure?
You have refractory edema, symptoms even at rest, and your heart has pretty much had it.
IV inotropes to keep you going till you can get a heart transplant.
Significant mortality risk.
WHy are ACE inhibitors indicated LONG before you have any hemodynamic issues (congestion… pump failure) with CHF?
ACE inhibitors prevent and may even reverse the effect of Angiotensin II’s mitogenic effects on the myocardium.
- Cardiac myocyte hypertrophy
- vascular smooth muscle hypertrophy
- Fibrosis of the heart and vessels;remodeling
- Atherosclerosis
SLOWS THIS CRITICAL PROCESS that has to happen for Heart Failure to occur.
WHich is better? ACE inhibitors or ARBs?
ACE inhibitors, because they’ve been shown to decrease morbidity and mortality in CHF.
There isn’t enough data on ARBs yet, so ACE inhibitors are preferred unless the patient can’t stand the cough (bradykinin buildup)
Does combining ACEi’s and ARBs have a beneficial effect?
Nope. No increased benefit. Take one or the other.
What is the name of the direct Renin inhibitor?
Aliskiren.
the one that ends in “REN” inhibits RENin.
Name the most common ACE inhibitors.
Captopril, Lisinopril.
Name the most common ARB.
Losartan.
What drug is renoprotective in diabetics?
Captopril (or any ACE inhibitor)
Side effects of ACE inhibitors.
most common: HYPOTENSION (esp. first dose)
2nd most common: DRY IRRITATING COUGH (bradykinin)
Others:
Na+ depletion (since you’re secreting it in urine)
Hyperkalemia (you retain it)
Andioedema
MOA and side effects of Aliskiren.
MOA: Direct inhibitor of Renin’s protease action (no Ang –>Ang1)
Toxicity: like the others…
Hypotension
Hyperkalemia
Andioedema
INHIBITS p-GLYCOPROTEIN, so be careful in use with antibiotics
Side effects of ARBS:
Hypotension
Hyperkalemia
Liver Dysfx
What B-blocker is approved in the US for HTN but NOT CHF?
Nebivolol (the 3rd generation with NO inducing activity)
BUT Docs use it off-label in the US anyway. It’s approved in Europe. Why not.
What are the beneficial effects of B-blockers in CHF?
Prevent B1 receptors from becoming over saturated and less responsive to Epi and NE. If chronically stimulated by Epi and NE, the B-receptors will down regulate and the heart will become less excitable, contributing to the heart failure.
There are 2 mechanisms/pathways of B-receptor activation.
- Acute stimulation/high receptor levels: leads to increased inotropic effects via increased calcium sensitivity, benefiting the heart. (no gene expression is altered)
- Chronic stimulation/lower receptor levels: myocyte hypertrophic effects via altered gene expression. (deleterious)
We just want to prevent the second one from happening.
What B-blocker is used the most for CHF?
Bisoprolol
Metoprolol
Carvedilol
Just a reminder… what are the 3 extra effects of Carvedilol?
Antioxidant activity
A antagonism
Ca2+ blocker
MOA of digoxin.
Increases the intracellular Ca2+ concentration by acting on 2 pumps:
Na+/K+ ATPase
Na+/Ca+ exchanger
Increases contractility of myocytes, thereby increasing SV.
(maintains CO)
increases inotropic response to endogenous neurotransmitters.
Talk about Digoxin.
Digoxin does 2 relatively contradictory things, and use depends on the situation. For CHF, we use it as a + inotrope.
Digoxin is a cardiac glycoside, and is beneficial because you can measure its serum levels and keep track of its usage (patient-specific)
Digoxin is most effective when used in conjunction with….
Vasodilators –> Decrease afterload
Diuretics –> reduce preload by keeping volume down
Your patient is starting to see Halos around lights, and feeling confused and tired. What do you need to give him to combat this drug toxicity? What drug is causing it?
Digoxin toxicity.
Give him DIGIBIND
Why is it important that the serum level of digoxin can be measured? (one of the only reasons it can even be used…)
Digoxin has a narrow therapeutic window that varies from person to person. Monitoring their response and simultaneous serum levels is the only way to safely treat a patient.
Does Digoxin use significantly lower morbidity and mortality in CHF patients?
YEP
What’s the EF threshold for Digoxin administration?
Use Digoxin when the EF < 25.
Name the most commonly used Loop Diuretic.
Furosemide
Name the 2 K+ sparing diuretics that are direct Aldosterone Inhibitors.
Spironolactone and Eplerenone
Main side effect of diuretics?
Electrolyte imbalance
Hypokalemia (except with spironolactone and eplerenone), Hyponatremia
Hypotension
Which of the diuretics improves survival and prognosis of a CHF patient?
Why?
Spironolactone and Eplerenone (the K+ sparing direct aldosterone inhibitors)
Why? Aldosterone has a mitogenic effect on the myocardium. (same reason ACE inhibitors improve morbidity/mortality….block the cause of cell growth)
Loop diuretics like Furosemide and Bumetide have no effect on morbidity/mortality.
How do vasodilators help in CHF?
Vasodilators cause decreased TPR, which lowers the BP, and decreases after load.
Name the main vasodilator drug.
HYDRALAZINE …. used only for patients who can’t tolerate ACE inhibitors.
NESIRITIDE –> human recombinant BNP
- naturally combats renin and aldosterone release
What effects does Nesiritide have on preload and after load?
LOWERS BOTH
What drugs are used to manage advanced CHF?
IV vasodilators : Nitrates , or Nesiritide for those who can’t tolerate nitrates.
IV inotropes: Dobutamine for a bit till you can get patient on Digoxin long term
TRANSPLANT
MOA of Dobutamine
B-agonist –> Works in absence of endogenous NTs
Only use as a transition drug
