April 4, 1977

Pharmacokinetics of Lidocaine

Author Affiliations

University of California San Francisco

JAMA. 1977;237(14):1433-1434. doi:10.1001/jama.1977.03270410033006

To the Editor.—  The recent article by Greenblatt et al stressed the advantages of using pharmacokinetic principles to choose dosage regimens for intravenous administration of the important antiarrhythmic drug lidocaine. The rationale was based on the assumption (largely proved) that given concentrations of the drug in plasma can be characterized as being subtherapeutic, therapeutic, or toxic. We agree with the approach that a good first approximation to using the drug is to set a target concentration that is therapeutic and to try to avoid subtherapeutic or toxic levels. However, we believe that the same principles used by Greenblatt and coworkers should be applied to produce an optimal, not simply adequate, concentration of the drug in plasma. Accordingly, we feel that the regimen proposed by Greenblatt et al has two problems. First, it yields a period of subtherapeutic drug concentration. The authors infer this may be the reason for the requirement