Clifford B. Walberg

Lidocaine efficacy and toxicity assessed by a new, rapid method

Lidocaine (L) levels were measured by gas chromatography (GC) and a new technique of direct measurement by enzyme immunoassay (EMIT) in 50 consecutive patients admitted to the Coronary Care Unit who received L. There was no significant difference between the levels by the two techniques. There was eradication of most ventricular arrhythmias in 78% of patients, partial effectiveness in 16%, and no improvement in 6%. Toxicity was mainly mild central nervous system effects, noted in 26 of the 50 patients. All six patients with serum L above 5.9 μg/ml had signs of toxicity. EMIT was found to be accurate and much faster than the traditional GC method.

Rapid assessment of lidocaine in cardiac patients by enzyme immunoassay.

Summary Lidocaine, a drug commonly used via intravenous infusion for the treatment of cardiac arrhythmias, is frequently effective but has the hazard of potential toxicity. Avoidance of toxicity and better control of therapy are shown to be markedly enhanced by a new method of rapidly measuring blood levels of lidocaine by enzyme immunoassay. Examples of the use of this technique for drug monitoring in the settings of suspected toxicity, prospective therapy, dose response assessment, and the study of pharmacokinetics are presented.