Name: Quinidine (Quinidex)
Class: Antidysrhythmic Agent (Class IA)
Mechanism: Binds to open and inactivated Na+ channels and prevents Na+ influx ® slowing of the rapid upstroke during phase 0. Also decreases the slope of phase 4 spontaneous depolarization. Prolongs repolarization. Inhibits arrhythmias due to normal automaticity. Intermed. speed of dissociation from Na+ channels.
Absorption: Oral ® rapid, nearly complete absorption.
Dist.: Metabolism.: Excretion, t½:
Toxicity/S.E.s: Proarrhythmic effects, negative inotropy, infranodal conduction block, DILQT. Cinchonism—n/v/d, tinnitus, headache, vertigo, auditory/visual disturbances. Hypotension (a-blocking activity). digoxin levels. Hypersensitivity rxns—rash, fever, angioneurotic edema, hepatitis. Reversible thrombocytopenia.
Utility: Treat atrial, AV junctional, & ventricular tachyarrhythmias. Maintain sinus rhythm after direct current cardioversion of atrial flutter or fibrillation. Prevent frequent ventricular tachycardia.
Special Features: