Antidysrhythmics Drugs Flashcards
Dysrhythmias/Arrhythmias
Defined as an abnormality in the rhythm of the heartbeat.
2 Basic types:
Tachydysrhythmias (increased heart rate)
Largest group of dysrhythmias
Bradydysrhythmias (decreased heart rate)
Atrial dysrhythmias prevent
proper filling of the ventricles, decrease cardiac output & can lead to blood pooling & clotting
Ventricular dysrhythmias are life-threatening because
inadequate filling & pumping can lead to decreased or absent cardiac output.
Symptoms of dysrhythmias:
Palpitations Angina Dyspnea Faintness Death
Supraventricular tachycardia
HR 150-250
Cardiac Action potentials
virtually all drugs used to tx dysrhythmias can also cause dysrhythmias.
Types of Antidysrhythmic Drugs
class 1 to 5
Antidysrhythmic Drugs Class I: Sodium Channel Blockers (Phase 0)
Slows Conduction & delays repolarization (blocks k+ channels)
Quinidine
interacts with digoxin
class 1B
Slows conduction, reduces automaticity & accelerates repolarization. (Little/no effect on EKG)
Lidocaine (IV)
class 1C
Reduce conduction velocity & delay ventricular repolarization.
Flecainide
Propafenone
Antidysrhythmic Drugs Class II: Beta Adrenergic Blockers (Phase 2 & 4)
Nearly identical to Class IV: CCBs
Acebutolol
Propanolol
Esmolol
Sotalol
Antidysrhythmic Drugs Class III: Drugs that Delay Repolarization (Phase 3)
block K channels; used for dysrhythmias; delays repolarization;
Sotalol
Amiodarone
Amiodarone
Approved for treatment of life-threatening ventricular dysrhythmias
no grape fruit juice
TOXICITY
Antidysrhythmic Drugs Class IV: Calcium Channel Blockers (Phase 2 & 4)
Drugs that delay repolarization
Nearly identical to Class II: Beta Blockers
diltiazem
verapamil