dysrythmias Flashcards
class IA Na blocker mechanism:
slows phase 0 depolarization
class IB Na blocker mechanism:
shortens phase 3 repolarization
class IC Na blocker mechanism:
markedly slows phase 0 depolarization
class II beta-blocker mechanism:
suppress phase 4 depol
class III K+ blocker mechanism:
prolongs phase 3 repol
class IV Ca++ blocker mechanism:
shortens AP
Class IA drug. This drug blocks Na+ channels in their open (activated) or closed (inactivated) states. This drug slows phase 0 depol and suppresses arrhythmias caused by increased normal automaticity. This drug inhibits ectopic and ventricular arrhythmias. This drug is indicated for atrial and ventricular tachyarrhythmias, used to maintain sinus rhythm post cardioversion. What is this drug?
quinidine
contraindications for quinidine:
heart block, SA node dysfunction, cardiogenic shock, sever uncomplicated heart failure, schizophrenia, SLE w/ procainamide
ADRs of quinidine:
arrhythmias, N/V/D, cinchonism, metabolism inhibited by cimetidine, induced by phenytoin, rifampin, barbituates, decreases digoxin clearance
Class IA drug. This drug is a derivative of procaine. Actions similar to quinidine. This drug is metabolized to n-acetylprocainamide (NAPA) which prolongs duration of AP (class III properties). What is the drug?
procainamide
ADRs of procainamide:
hypotension with IV route thus give PO, 25-30% reversible lupus erythematous-like syndrome with chronic use, asystole or ventricular arrhythmias at toxic concentration, depression, hallucination, psychosis
Class IA drug. This drugs actions are similar to quinidine. This drug produces negative inotropic effects, decreasing contractility in LV dysfunction, contraindicated in heart failure, causes peripheral vasoconstriction. What is this drug?
disopyramide.
disopyramide is used to treat?
ventricular arrhythmias
Disopyramide is an alternative to:
procainamide and quinidine
disopyramide ADRs:
anticholinergic sides (urinary retention, blurred vision, dry mouth, constipation), proarrhythmic
Class IB. This drug is the prototype and DOC for emergency treatment of cardiac arrhythmias. This drug shortens phase 3 repolarization and decreases the duration of the action potential. This drug suppresses arrhythmias caused by abnormal automaticity. This drug does not cause a negative inotropic effect. This drug is indicated for ventricular arrhythmias post MI or arising from myocardial ischemia. What is this drug?
Lidocaine
what are the contraindications for lidocaine?
SA disorders. AV block
what are the ADRs for lidocaine?
confusion, slurred speech, drowsiness, parasthesias, agitation, cardiac arrhythmias
Class IB. This drug’s action’s are similar to lidocaine. This drug is indicated for chronic ventricular arrhythmias associated with previous MI. What is the name of this drug?
mexiletine