Push Dose Pearls: Cannabinoid Hyperemesis

Cannabinoid Hyperemesis Syndrome (CHS) continues to be a major clinical challenge in the emergency department. Patients present with severe abdominal pain, intractable vomiting, and significant fluid and electrolyte derangements. CHS often affects people who have been using cannabis routinely for months to years – it can be difficult for patients to understand that their symptoms are related to cannabis. 

Today, emergency pharmacist Haley Burhans joins us to discuss first-line treatments, fluid management, discharge strategies, and how to navigate these tough bedside conversations.

First-Line Therapies: Haldol vs. Droperidol

• Haloperidol (Haldol): Supported by the HAVOC trial (haloperidol vs. placebo), which showed a reduction in symptoms and ED length of stay.
• Droperidol: Highly effective alternative with similar dopaminergic mechanism of action. May carry a lower risk of extrapyramidal symptoms compared to haloperidol. 
• Capsaicin Cream: addresses the TRPV1 pathway thought to drive CHS. Patients often dislike it as it causes a burning sensation on the skin and can be inadvertently spread to eyes or face. Can be an option if symptoms persist after trying the above meds and hot showers aren’t feasible. 

Backup Options & Anti-Emetics

• Alternative Dopaminergic Agents: Metoclopramide or prochlorperazine can be used.
• Standard Anti-Emetics (e.g., Ondansetron):
  • Serotonergic anti-emetics generally fail to address the underlying CHS pathway.
  • However, a single dose of ondansetron given alongside a butyrophenone (haloperidol/droperidol) is reasonable if you suspect co-existing etiologies.

QTc Prolongation Warning:

Chronic vomiting leads to electrolyte depletion. Combining anti-emetics and haloperidol or droperidol increases the risk of QTc prolongation.

Baseline EKG: Not strictly required for every low-risk patient, but strongly recommended for patients with multiple risk factors (e.g., co-ingestion/use of methadone, history of heart failure, or severe baseline bradycardia).

Fluid Resuscitation & Electrolyte Management

CHS patients can vomit to the point of severe dehydration and profound electrolyte/acid-base derangements.

• Fluid Selection:
  • Normal Saline (NS): A solid choice for initial volume resuscitation when sodium and chloride are severely depleted.
  • Lactated Ringer’s (LR): Ideal as a follow-up or maintenance fluid because it contains a small amount potassium.
• Potassium Repletion: