Sodium channel blockers

Definition

Sodium channel blockers are a class of medications that inhibit the flow of sodium ions through sodium channels in cardiac cells, thereby affecting the heart's electrical activity. They are primarily used to treat various types of dysrhythmias by slowing down the rate of depolarization and conduction.

5 Must Know Facts For Your Next Test

1. Sodium channel blockers are categorized into three classes: Class IA, IB, and IC, based on their effects on the cardiac action potential.
2. Class IA drugs (e.g., quinidine) moderately block sodium channels and prolong repolarization.
3. Class IB drugs (e.g., lidocaine) weakly block sodium channels and shorten repolarization.
4. Class IC drugs (e.g., flecainide) strongly block sodium channels with minimal effect on repolarization.
5. Potential side effects include proarrhythmia, hypotension, and negative inotropic effects.

Review Questions

• What are the primary classes of sodium channel blockers and how do they differ?
• Which class of sodium channel blockers is known for its strong blockade of sodium channels with minimal effect on repolarization?
• What are some common side effects associated with sodium channel blockers?

Related terms

Dysrhythmia:

An abnormality in the rhythm of the heartbeat.

Action Potential:

The change in electrical potential associated with the passage of an impulse along the membrane of a muscle cell or nerve cell.

Proarrhythmia:

A condition where an antiarrhythmic drug causes new or worsened arrhythmias.