Response to cardiovascular toxicity.

To the Editor: I enjoyed reading the recent review on the cardiovascular effects of cocaine by Karch, (1) but was disappointed that our ideas and research regarding cocaine's electrophysiology and its ability to provoke arrhythmias (2-5) were not cited. In particular, the readers of the Journal are referred to a 2002 publication (5) that we prepared which summarizes our original work and that of others. In this paper, we construct two distinct profiles of patients with cocaine-induced arrhythmias (overdose situations--slow monomorphic ventricular tachycardia and recreational users--torsade de pointes) based upon published case reports combined with cocaine's basic effects on conduction and ion channels (fast on-off potassium blockade at low concentrations and slow on-off sodium blockade at higher levels). We further offer the possibility of a genetic predisposition of some patients to these events. Most of our thoughts and findings are clearly echoed in the paper by Karch, but for some reason we were not given credit.

Jerry L. Bauman, PHARMD, FACC 

Departments of Pharmacy Practice and Medicine

Section of Cardiology

University of Illinois at Chicago 

Chicago, IL

References

1. Karch SB. Cocaine cardiovascular toxicity. South Med J 2005:98:794-799.

2. Beckman KJ, Parker RB, Hariman RJ, et al. Hemodynamic and electrophysiologic actions of cocaine: effects of sodium bicarbonate as an antidote in dogs. Circulation 1991;83:1799-1807.

3. Bauman JL, Grawe JJ. Winecoff AP. et al. Cocaine-related sudden cardiac death: a hypothesis correlating basic science and clinical observations. J Clin Pharmacol 1994;34:902-911.

4. Liu D, Hariman RJ, Bauman JL. Cocaine concentration-effect relationship in the presence and absence of lidocaine: evidence for competitive binding between cocaine and lidocaine. J Pharmacol Exp Ther 1996;276:568-577.

5. Bauman JL, DiDomenico RJ. Cocaine-induced channelopathies: emerging evidence on the multiple mechanisms of sudden death. J Cardiovasc Pharmacol Ther 2002;7:195-202.

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