IV. ANTIARRHYTHMIC AGENTS
I. Quinidine
The use of quinidine has greatly decreased since the advent of other antiarrhythmic agents. Quinidine suppresses premature beats in about 60% of cases, but it is only partially effective with life-threatening arrhythmias. Because of rare but serious side effects, the use of the drug is questionable. Quinidine can precipitate ventricular fibrillation, which is the most dangerous abnormal heart rhythm, and cardiac arrest. It does not seem reasonable to give priority to a drug that may increase the risk of ventricular fibrillation and death. This agent increases the level of digoxin in the blood and when used concomitantly, care is necessary with digoxin and anticoagulants such as warfarin.