Nokea
A 62-year-old man is to receive lidocaine as treatment for a symptomatic dysrhythmia. Upon assessment, the nurse notes that he has a history of alcoholism and has late-stage liver failure. The nurse will expect which adjustments to his drug therapy?
- A. The dosage will be reduced by 50%.
- B. A diuretic will be added to the lidocaine.
- C. The lidocaine will be changed to an oral dosage form.
- D. An increased dosage of lidocaine will be prescribed so as to obtain adequate blood levels.
Correct Answer: A
Rationale: Lidocaine is metabolized by the liver, so in liver failure, a 50% dosage reduction is often necessary to prevent toxicity. Lidocaine is not given orally, diuretics are not added, and increasing the dose is unsafe.
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The nurse is preparing to administer a bolus dose of verapamil as follows: 'Give 5-mg bolus of verapamil, IV push, over 2 minutes. May repeat in 30 minutes if needed.' The medication is available in a 2.5-mg/mL strength solution. Identify how many milliliters will the nurse draw into the syringe for this dose.
Correct Answer: 2 mL
Rationale: To calculate: 2.5 mg/1 mL = 5 mg/x mL. Cross-multiply: (2.5 * x) = (1 * 5); 2.5x = 5; x = 5/2.5 = 2 mL.
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.
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.
A patient is in the emergency department with a new onset of rapid-rate atrial fibrillation, and the nurse is preparing a continuous infusion. Which drug is most appropriate for this dysrhythmia?
- A. Diltiazem
- B. Atenolol
- C. Lidocaine
- D. Adenosine
Correct Answer: A
Rationale: Diltiazem is used for rate control in atrial fibrillation by slowing AV node conduction, making it appropriate for rapid-rate atrial fibrillation. Atenolol, lidocaine, and adenosine are not primarily used for this purpose.
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.