Nokea
The nurse is reviewing the classes of antidysrhythmic drugs. Amiodarone is classified on the Vaughan Williams classification as a class III drug, which means it works by which mechanism of action?
- A. Blocking slow calcium channels
- B. Prolonging action potential duration
- C. Blocking sodium channels and affecting phase 0
- D. Decreasing spontaneous depolarization and affecting phase 4
Correct Answer: B
Rationale: Amiodarone, a Vaughan Williams class III drug, prolongs the action potential duration by delaying repolarization in phase 3, thus extending the refractory period. The other options describe mechanisms of other antidysrhythmic classes.
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The nurse is preparing to administer adenosine to a patient who is experiencing an acute episode of paroxysmal supraventricular tachycardia. When giving this medication, which is important to remember?
- A. The onset of action occurs within 5 minutes.
- B. The medication must be given as a slow intravenous (IV) push.
- C. Asystole may occur for a few seconds after administration.
- D. The medication has a long half-life, and therefore duration of action is very long.
Correct Answer: C
Rationale: Adenosine has a very short half-life (<10 seconds) and is given as a rapid IV push. A brief period of asystole may occur, which is expected due to its transient AV node blockade. Slow IV push or long half-life are incorrect.
A patient has been started on therapy of a continuous infusion of lidocaine after receiving a loading dose of the drug. The nurse will monitor the patient for which adverse effect?
- A. Drowsiness
- B. Nystagmus
- C. Dry mouth
- D. Convulsions
Correct Answer: D
Rationale: Lidocaine toxicity can cause convulsions due to central nervous system effects. Drowsiness, nystagmus, and dry mouth are not primary adverse effects of lidocaine.
The nurse is monitoring for adverse effects in a patient who is receiving an amiodarone infusion. Which are adverse effects for amiodarone? (Select all that apply.)
- A. Tachycardia
- B. Constipation
- C. Chest pain
- D. QT prolongation
- E. Headache
- F. Hypotension
- G. Blue-gray coloring of the skin on the face, arms, and neck
Correct Answer: B,D,F,G
Rationale: Amiodarone can cause constipation, QT prolongation, hypotension, and blue-gray skin discoloration due to its complex pharmacology. Tachycardia, chest pain, and headache are not typical adverse effects.
A patient is taking procainamide for a cardiac dysrhythmia. The nurse will monitor the patient for which possible adverse effect?
- A. Bradycardia
- B. Shortened QT interval
- C. Dyspnea
- D. Diarrhea
Correct Answer: D
Rationale: Procainamide, a class Ia antidysrhythmic, can cause gastrointestinal side effects like diarrhea. Bradycardia, shortened QT interval, and dyspnea are not commonly associated with procainamide.
A patient is in the intensive care unit because of an acute myocardial infarction. He is experiencing severe ventricular dysrhythmias. The nurse will prepare to give which drug of choice for this dysrhythmia?
- A. Diltiazem
- B. Verapamil
- C. Amiodarone
- D. Adenosine
Correct Answer: C
Rationale: Amiodarone is the drug of choice for ventricular dysrhythmias per Advanced Cardiac Life Support guidelines due to its effectiveness in stabilizing ventricular rhythms. Diltiazem, verapamil, and adenosine are used for other dysrhythmias.