Which two classes of antidysrhythmic drugs have nearly identical ...

[NguyenJ]

Which two classes of antidysrhythmic drugs have nearly identical cardiac effects?
 
  a. Beta blockers and calcium channel blockers
  b. Beta blockers and potassium channel blockers
  c. Calcium channel blockers and sodium channel blockers
  d. Sodium channel blockers and potassium channel blockers

Question 2

A patient with heart failure who has been given digoxin (Lanoxin) daily for a week complains of nausea. Before giving the next dose, the nurse will:
 
  a. assess the heart rate (HR) and give the dose if the HR is greater than 60 beats per minute.
  b. contact the provider to report digoxin toxicity.
  c. request an order for a decreased dose of digoxin.
  d. review the serum electrolyte values and withhold the dose if the potassium level is greater than 3.5 mEq/L.

[jamesnevil303]

Answer to Question 1

ANS: A
Calcium channel blockade has the same impact on cardiac action potentials as does beta blockade, so these agents have nearly identical effects on cardiac function; that is, they reduce automaticity in the SA node, delay conduction through the AV node, and reduce myocardial contractility. Potassium channel blockers act by delaying repolarization of fast potentials. Sodium channel blockers block sodium channels to slow impulse conduction in the atria, ventricles, and His-Purkinje system.

Answer to Question 2

ANS: A
Anorexia, nausea, and vomiting are the most common adverse effects of digoxin and should cause nurses to evaluate for more serious signs of toxicity. If the HR is greater than 60 beats per minute, the dose may be given. Nausea by itself is not a sign of toxicity. A decreased dose is not indicated. A serum potassium level less than 3.5 mEq/L is an indication for withholding the dose.