Objective: To assess the electrocardiographic safety profile of low-dose ziprasidone (< or =40 mg/day) among pediatric outpatients treated for up to 6 months.
Method: This was a prospective, open-label trial involving 20 subjects with a mean age of 13.2 +/- 3.0 years. Subjects received a mean ziprasidone dose of 30 +/- 13 mg/day and were followed for 4.6 +/- 2.0 months, receiving a median of nine electrocardiograms each (range 2-11; total, 176).
Results: There were statistically significant changes from baseline to peak values in heart rate, PR, and QTc intervals, but not in QRS complex width. The mean QTc prolongation was 28 +/- 26 milliseconds and not related to dose (r = 0.16, p = .07). The peak QTc of three subjects reached or exceeded 450 milliseconds; one subject experienced a 114-millisecond prolongation. There was poor agreement (kappa = 0.25) between automated and manual identification of long QTc intervals (> or =440 milliseconds).
Conclusions: These preliminary findings, occurring at doses low by current treatment standards, suggest that close electrocardiographic monitoring is warranted when prescribing ziprasidone to children, particularly at higher doses or when combined with other QTc-prolonging agents.