A recent prospective cohort study investigated the effect of low-dose droperidol on QTc in an emergency department:

• 68 patients
• Droperidol dose: median 1.875 mg (range: 0.625-2.5 mg)
• Given as a 2-minute bolus
• 94.1% received for headache management
• Mean change in QTc: +29.9 ms (SD 15)
• 17.6% (n=12) experienced QTc interval >=500 ms
• 4.4% (n=3) had a change >=+60 ms
• No serious arrhythmias or deaths
• 13.2% (n=9) had at least one non-serious event (restlessness and/or anxiety)

Low-dose droperidol has a small effect on QTc and most patients remained below 500 ms.

References

Hernández-Rodríguez L, Bellolio F, Cabrera D, et al. Prospective real-time evaluation of the QTc interval variation after low-dose droperidol among emergency department patients. Am J Emerg Med. 2022 Feb;52:212-219.