[Pharmacokinetics and plasma concentrations of anti-arrhythmic drugs]

The efficacy of antiarrhythmic drug treatment and the risk of toxicity can be evaluated by studying the relationship between these agents effects and their plasma concentrations. Optimal drug surveillance is not possible, however, unless: an effect-concentration relationship can be demonstrated; therapeutic and toxic plasma concentrations have been established; plasma concentrations in different patients demonstrate adequate dosage when measured after the administration of standard doses; a reliable and specific dosing method can be easily performed at a reasonable cost. Lidocaine, quinidine, and procainamide are among the commonly employed antiarrhythmic agents which fulfill all these requirements. Clinical pharmacologic studies are underway for disopyramide, amiodarone, mexiletine, propafenone and flecainide, and certain findings are already of value in hospital settings.