Class I Antidysrhythmic Therapy

Questions and Answers

Class IA antidysrhythmic drugs block primarily which channels?

Sodium

Which antidysrhythmic drug is indicated for atrial dysrhythmia?

Quinidine

Which antidysrhythmic drug is indicated for pulseless ventricular tachycardia?

Lidocaine

Match the subclass of antidysrhythmic to its corresponding mechanism of action.

Class IA = Slow conduction and prolong repolarization Class IB = Slow conduction and shorten repolarization Class IC = Prolong conduction with little or no effect on repolarization Signup and view all the answers

What symptoms would the nurse include when teaching Mr. A about cinchonism related to quinidine toxicity?

All of the above Signup and view all the answers

The presence of which disease process constitutes a contraindication for quinidine antidysrhythmic therapy?

Myasthenia gravis Signup and view all the answers

What may be the result of a drug-drug interaction when quinidine and digoxin are administered concurrently?

Digoxin toxicity Signup and view all the answers

What adverse outcome should the nurse alert the healthcare provider about in a patient taking flecainide?

Heart failure and worsening arrhythmias Signup and view all the answers

Which ECG change will the nurse monitor for when a patient is being treated with quinidine?

Widening of the QRS Signup and view all the answers

What therapeutic effect should the nurse monitor while administering quinidine?

Decreased heart rate Signup and view all the answers

What time frame after administration of flecainide would the nurse expect the onset of action to occur?

3 hours Signup and view all the answers

Which symptom, if reported by a patient recently started on quinidine, would the nurse find most concerning?

Shortness of breath Signup and view all the answers

While administering lidocaine, what adverse drug effect should the nurse monitor for?

Seizure Signup and view all the answers

What teaching will the nurse provide regarding long, hot baths for a patient prescribed quinidine?

Avoid long, hot baths Signup and view all the answers

The patient with which medical condition will most likely benefit from lidocaine administered intravenously?

Acute ventricular tachycardia Signup and view all the answers

Before administering quinidine, what contraindication should the nurse assess the patient for?

Complete heart block Signup and view all the answers

Study Notes

Class I Antidysrhythmic Therapy Overview

Class IA antidysrhythmic drugs primarily block sodium channels, slowing electrical impulses in the heart.
Quinidine, a Class IA drug, is used for both atrial and ventricular dysrhythmias.

Indications for Use

Lidocaine is indicated for pulseless ventricular tachycardia.
Quinidine is contraindicated for patients with myasthenia gravis due to adverse effects from anticholinergics.

Subclass Mechanisms of Action

Class IC: Prolong conduction with minimal effect on repolarization.
Class IA: Slow conduction and prolong repolarization.
Class IB: Slow conduction and shorten repolarization.

Monitoring and Adverse Effects

Monitor for cinchonism symptoms (tinnitus, nausea, visual disturbances) in patients receiving quinidine.
Heart failure and worsening arrhythmias may occur with flecainide; assess and alert healthcare providers.
ECG changes from quinidine treatment include widening of the QRS complex and prolonged QT interval, which may indicate toxicity.
Lidocaine can cause seizures; monitor patients closely for this effect.

Patient Management

Advise patients on quinidine to avoid long, hot baths due to the potential for hypotension.
Expect quinidine to decrease heart rate as a therapeutic effect.
The onset of action for flecainide occurs approximately three hours after administration.
Shortness of breath after starting quinidine therapy may suggest a pulmonary embolus and should be reported immediately.

Drug Interactions and Dosage Adjustments

Concomitant use of quinidine and digoxin can lead to digoxin toxicity; it may require a reduction in digoxin dosage due to increased serum levels.

Specific Cases

Patients with acute ventricular tachycardia are best treated with intravenous lidocaine.
Assess for contraindications such as complete heart block before administering quinidine.

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Description

Test your knowledge on Class IA antidysrhythmic drugs and their mechanisms. This quiz covers key concepts about sodium channel blockers and their applications in treating atrial dysrhythmias. Perfect for medical students and healthcare professionals alike.