Quinidine

Definition

Quinidine is a Class I antiarrhythmic drug that works by blocking sodium channels in the heart. It is used to treat various types of cardiac dysrhythmias, such as atrial fibrillation and ventricular tachycardia.

5 Must Know Facts For Your Next Test

1. Quinidine can prolong the QT interval, increasing the risk of torsades de pointes.
2. It decreases myocardial excitability and conduction velocity.
3. Common side effects include gastrointestinal disturbances and cinchonism (tinnitus, headache, nausea).
4. Quinidine is metabolized by the liver and excreted in urine; dose adjustments may be necessary in hepatic or renal impairment.
5. It has interactions with other drugs like digoxin and warfarin, which may require monitoring.

Review Questions

• What class of antiarrhythmic drugs does Quinidine belong to?
• Name two types of cardiac dysrhythmias that Quinidine is used to treat.
• What are some common side effects associated with Quinidine?

Related terms

Lidocaine: A Class IB antiarrhythmic drug used primarily for ventricular arrhythmias.

Procainamide: Another Class IA antiarrhythmic similar to Quinidine but with different side effect profile.

Amiodarone: A Class III antiarrhythmic agent that affects potassium channels and is used for both atrial and ventricular arrhythmias.