Treatment of THC-Induced Hyperemesis (Cannabinoid Hyperemesis Syndrome)
The definitive treatment for cannabinoid hyperemesis syndrome (CHS) is complete and permanent cessation of all cannabis use, which is the only intervention that leads to long-term resolution of symptoms. 1, 2
Acute Emergency Department Management
Initial Assessment and Diagnosis
- Suspect CHS in any patient with cyclic vomiting who uses cannabis regularly (especially >4 times weekly for >1 year) 1, 2
- Look for the pathognomonic feature: compulsive hot water bathing behavior for symptom relief, present in 44-71% of cases 2, 3
- First, rule out life-threatening conditions including acute abdomen, bowel obstruction, mesenteric ischemia, pancreatitis, and myocardial infarction before confirming CHS 1, 2, 3
Acute Pharmacological Treatment (in order of efficacy)
First-line: Benzodiazepines
- Benzodiazepines (particularly lorazepam) are the most effective acute treatment for nausea and vomiting in CHS based on multiple prospective studies 3, 4, 5
- They work by decreasing CB1 receptor activation in the frontal cortex and reducing anticipation of nausea through sedative effects 4
Second-line: Haloperidol
- Haloperidol is the second-line agent for acute symptom control 3, 5
- Butyrophenones like haloperidol reduce hospital length of stay by nearly 50% (6.7 vs 13.9 hours, p=0.014) 2
Adjunctive: Topical Capsaicin
- Apply capsaicin 0.1% cream to the abdomen, which activates TRPV1 receptors 1, 2, 3, 5
- Monitor closely for efficacy and adverse effects 3
Limited efficacy: Ondansetron
- Ondansetron may be tried but often has limited efficacy compared to its use in other conditions 1, 3
Never use: Opioids
- Avoid opioids entirely as they worsen nausea, carry high addiction risk, and do not address the underlying pathophysiology 1, 2, 3
Supportive Measures
- Hot showers or baths (hydrothermotherapy) provide temporary symptomatic relief and serve as a diagnostic clue 1, 6, 5
Long-Term Management Strategy
Cannabis Cessation (Essential)
- Cannabis cessation counseling is both diagnostic and the only definitive treatment 1, 2, 3
- Complete symptom resolution requires at least 6 months of continuous cannabis abstinence, or abstinence duration equal to at least 3 typical vomiting cycles for that patient 2, 3
- This is the only reliable criterion that separates CHS from cyclic vomiting syndrome 2
Preventive Pharmacotherapy
- Tricyclic antidepressants (particularly amitriptyline) are the mainstay of long-term preventive therapy 1, 2, 3
- Start at 25 mg at bedtime and titrate weekly by 25 mg increments to reach the minimal effective dose of 75-100 mg 1, 2, 3
Psychological Support
- Provide psychological support as anxiety and depression are common comorbidities 1, 2
- Consider co-management with psychiatry for patients with extensive psychiatric comorbidity or treatment resistance 1
Critical Diagnostic Pitfalls to Avoid
- CHS is frequently underdiagnosed or misdiagnosed due to limited clinician awareness, leading to extensive unnecessary testing 2, 5, 7
- Do not pursue exhaustive investigations once CHS is suspected; instead focus on early diagnosis to facilitate treatment 3
- Directed questions about cannabis use and the effect of hot showers on symptoms frequently confirm the diagnosis 5
- Remember that edible cannabis consumption can also cause CHS, as the syndrome is triggered by chronic THC exposure regardless of route of administration 2
Cannabis Withdrawal Syndrome (Important Distinction)
- Approximately 47% of regular cannabis users experience cannabis withdrawal syndrome (CWS) after cessation 3
- CWS presents oppositely to CHS: vomiting occurs after stopping cannabis in CWS versus during active use in CHS 3
- CWS symptoms (irritability, anxiety, insomnia, decreased appetite, GI symptoms) typically onset within 24-72 hours of cessation, peak between days 2-6, and resolve within 1-2 weeks 3
- Manage CWS with standard antidiarrheal agents like loperamide for GI distress, avoid opioids, and provide psychological support 3