Sir: The exact statement in my article is as follows: “One study showed that risperidone, olanzapine, quetiapine, and haloperidol had a negligible effect on QTc, but ziprasidone and thioridazine caused a clinically significant increase” (p. 4).1 This statement does not imply that the QTc prolongation associated with ziprasidone and thioridazine was the “same” but rather that both drugs were associated with this change to a greater extent than other antipsychotics tested. Secondly, Drs. Ortega et al. state that the QTc prolongation for ziprasidone and other antipsychotics (olanzapine, risperidone, quetiapine, haloperidol) were “comparable” based on the 054 study. The statement in the U.S. label for ziprasidone based on the results of the 054 study is “The mean increase in QTc from baseline for ziprasidone ranged from approximately 9 to 14 msec greater than for 4 of the comparator drugs (risperidone, olanzapine, quetiapine, and haloperidol), but was approximately 14 msec less than the prolongation observed for thioridazine.”2 The U.S. label for ziprasidone includes a bolded warning regarding QT prolongation. It is true that there were no clinical events associated with this increase noted in the clinical trials. I refer Drs. Ortega et al. to my article3 (from which this report was extracted as a summary) for a more complete discussion of this issue.
Footnotes
Dr. Sharif has served as a consultant for and received grant/research support from Janssen and has received honoraria from and served on the speakers/advisory boards of Bristol-Myers Squibb and Janssen.
References
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- Sharif ZA. Overview of safety and tolerability of atypical antipsychotics used in primary care. Primary Care Companion J Clin Psychiatry. 2003 5suppl 3. 14–21. [Google Scholar]