Drugs to treat heart failure Flashcards
Diuretics, ACE inhibitors, B-agonists, B blockers
What do venodilator drugs do for Heart failure
reduce preload
-redistributes blood from the chest and toward the peripheral veins
what drugs are used first in chronic heart failure
4
- diuretics
- ACE inhibitors
- B-agonists
- B-blockers
What therapies are used in acute heart failure
6 total
- diuretics
- vasodilators
- beta-agonists
- bipyridines
- natiuretic peptide
- L ventriculsar assist devies
What therapies are used in chronic heart failure
List 8
- diuretics
- aldosterone receptor antagonists
- ACE inhibitors
- Angiotensin receptor blockers
- Beta Blockers
- Cardiac glycosides
- vasodilators
- cardiovesrsion
what are cardiac glycosides? what is the MOA
Digoxin
inhibits Na+/K+ATPase
Main indications of Digoxin
- A-fibb
- Heart failure
in treatment resistant cases
What should happen post-digoxin administration
monitor the serum concentration (bc narrow therapeutic index)
Symptoms of cardiac glycoside (digoxin) poisoning
4
- nausea
- vomiting
- blurry visino
- cardiac arrhythmias that cause death
Is digoxin quickly overdosed? why
yes it is quickly overdosed because of the narrow therapuetic index
Firrst line treatment for cardiac glycoside poisoning
administration of digoxin-specific antibodies
What is the onset of effect of Digoxin
oral: 30 minutes-2hours
IV: 15-30 minutes
What is the half life of digoxin
36-40 hours
what is the clearance rate of Digoxin
renal clearance is proportional to creatinine clearance
What is the protein binding percentage of digoxin
20-40%
When is Digoxin indicated
- congestive heart failure (symptomatic patients with NYHA >11 despite prior tx)
- A-fibb
- SVT
what is the dosage of digoxin in adult patients with HFrEF <70 yo
Maintenance dose of
Oral: 0.125 or 0.25mg QD
What 3 factors indicated dosage change of digoxin? What should the dose be?
- > 70yo
- renal dysfunction
- low lean body mass
Low dose: 0.125mg daily or every other day
What happens to dosage when changing digoxin from PO to IV?
reduce dosage by 20-35%
When can toxicity of digoxin occur? What should you do to prevent toxicity of digoxin
therapuetic concentrations, renal impairment
monitror serum digoxin
Pharmodynamics of digoxin
inhibits Na+/K+ATPase: which causes high Na+ ICF, reduced efficacy of Na+/Ca2+ exchangers, which results in high ICF Ca2+
What does digoxin do to the cardiomyocytes
-positive inotropic effect
-negative dromotropic effect via AV node depression
-negative chronotropic effect via SA node depression
What does digoxin do to neurons of the vagal nerve
- increased velocity of electric conduction
- reduced heart rate
are toxic effects of cardiac glycosides in the GI tract
- anorexia
- nausea
- vomiting
- diarrhea
Cardiac glycosides effect on CNS
- vagal and chemoreceptor trigger zone stimulation
- disorientation and hallucinations (esp in eldery)
- visual disturbances
What two ways do digitalis and K+ interact?
- inhibit binding eachother to Na+/K+ATPase (hypo and hyperkalemia)
- increased cardiac automaticity is inhibited by hyper kalemia (digitalis toxicity is inhibited)
How does calcium increase the risk of digitalis induced arrhythmia?
excess calcium accelerates the overloading of intracellular calcium stores
Types of drugs without positve inotropic effects used in heart failure
- diuretics
- ACE inhibitors (-pril)
- Angiotensin receptor antagonists (-sartans)
- Aldosteron antagonists (-one)
- B-blockers (-lol)
what can Vasodilators do to treat acute heart failure
- reduction in preload (through venodilation)
- reduction in afterload (through arteriolar dilation)
- Bonus** hydralazine and isosorbide dinitrate reduce damaging of remodeling of the heart**
why are beta blockers used to treat heart failure?
decrease the workload
Acute heart failure episode associations?
list 6
- increased exertion
- stress
- excess salt intake
- nonadherence to medical therapy
- increase metabolic demand (fever, anemia, etc)
- AMI
