The cardiovascular safety of lubeluzole was evaluated in patients with ischemic stroke in a double-blind, placebo-controlled trial. Forty-six patients were randomized to receive a continuous daily infusion of lubeluzole 5 mg (loading dose 3.75 mg over 1 h), lubeluzole 10 mg (loading dose 7.5 mg over 1 h), or placebo for 5 days within 24 h of stroke onset. The primary measure of cardiovascular safety was the QTc interval, derived from the continuous electrocardiogram (ECG) and measured during treatment and a 2-day follow-up. Compared with placebo. Neither dosage of lubeluzole had any statistically or clinically relevant effects on the QTc. Neither were there any significant differences among the three treatment groups in the area under the curve for heart rate, QT interval, QT dispersion, or QTlc. Lubeluzole did not increase the frequency of ECG abnormalities. No ventricular fibrillation, ventricular tachycardia, or torsades de pointes were observed in any of the treatment groups. During this trial, 3 patients in the placebo group and 2 patients in the lubeluzole 5-mg group died. There were no deaths in the lubeluzole 10-mg group. Adverse experiences were similar in all three treatment groups except that superficial thrombophlebitis was more frequent in the lubeluzole 10-mg group. In doses to 10 mg/day, lubeluzole has a favorable cardiovascular safety profile, as demonstrated by the lack of clinically relevant effects on heart rate, QT, QTc, and QTlc, and it was well tolerated by patients with ischemic stroke.