Ch 21 Cardiac Glycosides & HF Flashcards
What are the meds for choice for HF
ACE INHIBITORS
ARBs
Beta blockers
What is a secondary med given if the choice of meds for HF Are unaffected
Cardiac glycosides
What is the prototype drug of cardiac glycosides
Digoxin ( lanoxin, lanoxicaps, digitek)
What is the pharmalogical action of cardiac glycosides
Positive inotropic effect= increased force of myocardial contraction this improves SV and cardiac output
Neg inotropic effect= decreased HR
at therapeutic levels, digoxin slows the rate of SA NODE depolarization and the rate of of impulses thru the conduction system of the heart
A decreased HR gives the ventricle more time to fill with blood coming from the atria, which leads to increased SV and increased CO
What are the therapeutic uses of cardiac glycosides
Treatment of HF
dysrhythmias ( atrial fibrillation)
What are the adverse effects of cardiac glycosides
Dysrhythmias
Cardio toxicity
GI effects include anorexia, nausea, vomiting and abdominal pain
CNS effects include fatigue, weakness, vision changes,
What are serum K+ levels
3.5-5
What are therapeutic serum levels of digoxin
0.5-2
Cardiac glycosides are contraindicated in what
Pregnancy category C
cilents who have disturbances in ventricular rhythm, including ventricular fibrillation, ventricular tachycardia and 2nd and 3rd degree heart block.
Use cautiously in ppl who have hypokalemia, partial AV block, advanced HF and renal insufficiency
What are medication food interactions of cardiac glycosides
Thiazides diuretics and loop diuretics may lead to hypokalemia,which increases the risk of developing dysrhythmias
Ace inhibitors and ARBs increase the risk of hyperkalemia which can lead to decreased effects of digoxin
Sympathomimetic meds such as dopamine
Quinidine increases the risk of digoxin toxicity
Verapamil increases plasma levels of digoxin
Antacids decrease absorption of digoxin
What are indications of digoxin toxicity
Fatigue, weakness, vision changes, GI effects
When administering digoxin via IV what is a priority
Infuse over at least 5 min and monitor for dysrhythmias
How can a nurse manage digoxin toxicity
- Digoxin and K+”sparing meds should be stopped immediately
- Monitor k+ levels… For levels less than 3.5 administer k+ IV or PO
- Treat dysrhythmias with phenytoin or lidocaine
- Treat bradycardia with atropine
- For excessive overdose, activated charcoal, cholestyramine, or digiblind can b used to bind digoxin
How can a nurse tell if digoxin therapy is effective
Control of HF
Absence of cardiac dysrhythmias
What is the prototype drug of ADRENERGIC AGONISTS
Catecholamines
- epinephrine ( adrenaline)
- dopamine ( Inotropic)
- dobutamine
Other meds:
* Isoprotenerol: Catecholamine
Terbutaline: noncatecholamine
What is the purpose of alpha1?
Activation of receptors in arterioles of skin, viscera, and mucous membranes, and veins leads to vasoconstriction
What is the purpose of beta1
Heart stimulation leads to increased HR, increased myocardial contractility, and increased rate of conduction through the AV node
Activation of receptors in the kidney lead to the release of renin
What is the purpose of beta2
Activation of receptors in the arterioles of the heart, lungs and skeletal muscle leads to vasodilation
Bronchial stimulation leads to bronchodilation
Activation of receptors in the uterine smooth muscle causes muscle relaxation
Activation of receptors in the liver causes glycogenolysis
Skeletal muscle receptor activation leads to muscle contraction
What is the purpose of dopamine
Activation of receptors in the kidney cause the renal blood vessels to dilate
What is the therapeutic use of alpha1
Slows absorption of local anesthetics
Manages superficial bleeding
Decreased congestion of nasal mucous
Increased BP
What Is the therapeutic use of beta1
Treatment of AV block and cardiac arrest
What is the therapeutic use of beta2
Asthma
A low dose of dopamine is used for what
Shock
HF
BY THE EFFECT OF RENAL BLOOD VESSEL DILATION
What are adverse effects of epinephrine
Vasoconstriction fro activation of alpha1 receptors in the heart can lead to hypertensive crisis
Beta1 receptor activation in the heart can cause dysrhythmias, beta1 receptor activation also increases O2 demand, leading to the development of angina
What are adverse effects of dopamine
Beta1 receptor activation in the heart can cause dysrhythmias, it also increases the workload of the heart and increase O2 demand, leading to development of angina
Necrosis can occur fro extravasation of high doses of dopamine
What are adverse effects of dobutamine
Increased HR
What pregnancy category is epinephrine and dopamine
C
What pregnancy category is dobutamine
b
Epinephrine, dopamine, and dobutamine should be used cautiously in who
Clients who have hyperthyroidism, angina, history of MI, HTN, and diabetes
What drug should be avoided while using epinephrine
MAOIs, which can prolong the effects of epinephrine
TCAs block uptake of epinephrine, which will prolong and intensify effects of epinephrine
General anesthetics can cause the heart to become hypersensitive to the effects of epinephrine, leading to dysrhythmias
What promotes beneficial effects of dopamine
Diuretics
What drug may be used to treat epinephrine toxicity
Phentolamine
What med can place a client at risk for digoxin toxicity
Verapamil ( Calan) a calcium channel blocker can increase digoxin levels
What are indications of digoxin toxicity
Fatigue,
Anorexia
Diplopia
If a clients digoxin level is 0.25 what should the nurse anticipate
An increase in the clients digoxin dose.
The inability of the heart to pump blood sufficiently results in what
Decreased tissue perfusion
Left side HF- dyspnea, cough, and oliguria
Right side HF- systemic congestion with peripheral edema, jugular vein distention and wt gain
