Emergency Department Management of Cannabis Hyperemesis Syndrome
Initial Approach
For acute CHS management in the ED, prioritize butyrophenones (haloperidol or droperidol) as first-line therapy, which reduce hospital length of stay by nearly 50% (6.7 vs 13.9 hours), combined with topical capsaicin 0.1% cream to the abdomen and benzodiazepines for refractory symptoms. 1
Before confirming CHS, rule out life-threatening conditions including acute abdomen, bowel obstruction, mesenteric ischemia, pancreatitis, and myocardial infarction. 1, 2
Diagnostic Confirmation in the ED
Suspect CHS when patients present with:
- Stereotypical episodic vomiting (≥3 episodes annually, acute onset, duration <1 week) 1
- Cannabis use pattern: >1 year of use before symptom onset, frequency >4 times weekly 1, 2
- Pathognomonic hot water bathing behavior (compulsive hot showers/baths for relief), present in 44-71% of cases 1
- Abdominal pain accompanying vomiting episodes 1
The diagnosis is clinical—avoid extensive unnecessary testing once CHS is suspected. 1
Pharmacologic Treatment Algorithm
First-Line Therapy
Haloperidol or droperidol are superior to conventional antiemetics and should be prioritized. 1 These butyrophenones address the dysregulated endocannabinoid system and provide powerful sedating effects that target the stress-mediated component of CHS. 1, 3
Topical capsaicin 0.1% cream applied to the abdomen activates TRPV1 receptors and provides consistent benefit. 1, 2 This should be used as an adjunct to antipsychotics. 1
Second-Line Therapy
Benzodiazepines (particularly lorazepam) are highly effective for acute nausea and vomiting in CHS, addressing the stress-mediated component through sedating and anxiolytic effects. 1, 4, 3 Multiple case series and prospective studies support benzodiazepines as the most effective acute treatment. 5
Limited Efficacy Options
Ondansetron and conventional antiemetics may be tried but often have limited efficacy compared to their use in other conditions. 2, 6 Standard antiemetics frequently fail in CHS due to the unique pathophysiology involving CB1 receptor dysregulation in the dorsal vagal complex. 1
Promethazine and olanzapine can be considered as alternative antipsychotics if haloperidol is unavailable. 2, 7
Contraindicated Therapy
Avoid opioids entirely—they worsen nausea, carry high addiction risk, and do not address the underlying pathophysiology of CHS. 1, 2, 5 This is a critical pitfall to avoid, as CHS patients are often exposed to unnecessary opioids during repeated ED visits. 7
Non-Pharmacologic Management
Hot showers or baths (hydrothermotherapy) provide temporary symptomatic relief and serve as both a diagnostic clue and immediate comfort measure. 2, 4
Critical Counseling
Cannabis cessation is the only definitive cure and must be strongly emphasized during the ED visit. 1, 2 Complete symptom resolution requires at least 6 months of continuous cannabis abstinence or duration equal to 3 typical vomiting cycles for that patient. 1, 2
Inform patients that:
- Symptoms will only resolve with complete and sustained cannabis abstinence 1
- Tricyclic antidepressants (amitriptyline 75-100 mg at bedtime) are the mainstay of long-term preventive therapy 1, 2
- Follow-up with primary care or gastroenterology is essential for ongoing management 2
Common Pitfalls
Do not confuse CHS with Cannabis Withdrawal Syndrome (CWS)—they present oppositely. 5 CHS occurs during active chronic cannabis use with vomiting episodes, while CWS occurs 24-72 hours after stopping cannabis with irritability, anxiety, and GI symptoms that resolve within 1-2 weeks. 5 The management strategies are opposite: CHS requires cessation, while CWS requires supportive care. 5
Avoid extensive workups once CHS is clinically suspected—this leads to unnecessary testing, procedures, and healthcare costs. 1, 4 Focus on early diagnosis to facilitate appropriate treatment. 5