HaVOC RCT – Haloperidol for Cannabis Hyperemesis

Written by Vivian Lei

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Haloperidol was superior to ondansetron for treatment of vomiting and abdominal pain associated with cannabis hyperemesis syndrome in this randomized clinical trial.

Why does this matter?
Cannabis hyperemesis syndrome is often resistant to traditional first-line antiemetics, and anecdotal evidence has suggested haloperidol may be effective.

Happy holidays with hot showers and Haldol
In this blinded, randomized controlled crossover trial in regular cannabis users presenting with suspected hyperemesis at 2 Canadian EDs, 33 patients were randomized to receive either IV ondansetron 8 mg or haloperidol (0.05 or 0.1 mg/kg). Researchers assessed change in abdominal pain and nausea on a 10 cm visual analog scale (VAS). Patients receiving haloperidol at any dose had a larger reduction in abdominal pain and nausea within 2 hours of administration than ondansetron (mean difference between groups was 2.3 cm on VAS). Haloperidol also resulted in higher treatment success (54% vs 29%). The haloperidol group saw reduced use of rescue antiemetics (31% vs 59%), benzodiazepines (8% vs 41%), or any medication (31% vs 76%). Time to discharge for the haloperidol group was lower at 3.1 vs 5.6 hours. Two patients in the higher dose haloperidol group returned to the ED for acute dystonia.

This trial struggled with low enrollment and was apparently halted early for efficacy due to a “stronger than anticipated” effect size. While this does run the risk of overstating treatment benefit, this offers at least some initial evidence that low dose haloperidol is a more effective first-line treatment for cannabis hyperemesis syndrome than ondansetron.

Source
Intravenous Haloperidol Versus Ondansetron for Cannabis Hyperemesis Syndrome (HaVOC): A Randomized, Controlled Trial. Ann Emerg Med. 2020 Nov 5;S0196-0644(20)30666-1. doi: 10.1016/j.annemergmed.2020.08.021. Online ahead of print.

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