Remember your chronic cannabinoid user that comes in with hyperemesis. They have Cannabinoid hyperemesis syndrome (CHS): cyclic abdominal pain, nausea, and vomiting in the setting of chronic cannabis use.
You try every anti-emetic in your ED but still vomiting. These patients usually get relief from hot showers but of course your patient already knows that and tried it before they came in to the ED.
Next time try capsaicin cream (0.075%) to the abdomen (or technically hot sauce).
How does this work you ask? It has something to do with TRPV1 receptor that is found in the peripheral nervous system and activated by exposure to high temps and capsaicin. Capsaicin binds to TRPV1 and impairs substance P signaling to hypothalamus. This is also why hot showers work.
Dezieck L, et al. Resolution of cannabis hyperemesis syndrome with topical capsaicin in the emergency department: a case series. Clin Toxicol (Phila). 2017 Sep; 55(78): 908-913.