What is the most effective treatment for cannabinoid hyperemesis syndrome (CHS)?

Treatment of Cannabinoid Hyperemesis Syndrome

The definitive treatment for cannabinoid hyperemesis syndrome (CHS) is complete cessation of cannabis use, which is the only intervention that leads to long-term resolution of symptoms. 1

Acute Management

• Topical capsaicin (0.1%) applied to the abdomen is an effective first-line treatment that provides symptom relief by activating transient receptor potential vanilloid type 1 receptors 2, 1
• Antipsychotics are effective for acute symptom management:
  • Haloperidol 2, 1
  • Promethazine 2, 1
  • Olanzapine 2, 1
• Benzodiazepines can provide relief in the acute setting 2, 3
• Ondansetron may be tried but often has limited efficacy compared to its use in other conditions 1, 4
• Hot showers or baths (hydrothermotherapy) provide temporary symptomatic relief and can be a diagnostic clue 1, 5
• Avoid opioids as they may worsen nausea and carry addiction risk 2, 1

Emergency Department Approach

1. Rule out life-threatening conditions first (acute abdomen, bowel obstruction, mesenteric ischemia, pancreatitis, myocardial infarction) 2, 6
2. Consider CHS in patients with:
   • Regular cannabis use (especially >4 times weekly for >1 year) 1, 6
   • Cyclic vomiting episodes (≥3 episodes annually) 2, 1
   • Relief with hot showers/baths 5, 7
3. Provide supportive care with:
   • Intravenous fluids for dehydration 5, 7
   • Appropriate antiemetics as outlined above 2, 3

Long-term Management

• Cannabis cessation counseling is essential as the only definitive treatment 1, 5
• Tricyclic antidepressants (particularly amitriptyline) are the mainstay of long-term therapy:
  • Start at 25 mg at bedtime
  • Titrate weekly to reach minimal effective dose of 75-100 mg 2, 1
• Psychological support may be beneficial as anxiety and depression are common comorbidities 1, 6
• Consider co-management with psychiatry for patients with extensive psychiatric comorbidity or treatment resistance 1, 6

Diagnostic Criteria for CHS

CHS should be diagnosed based on:

• Clinical features: stereotypical episodic vomiting (≥3 episodes annually) 2, 1
• Cannabis use patterns: >1 year of use before symptom onset, frequency >4 times weekly 2, 1
• Cannabis cessation: resolution of symptoms after abstinence for at least 6 months or duration equal to 3 typical vomiting cycles 2, 1

Common Pitfalls and Caveats

• CHS is often underdiagnosed or misdiagnosed due to limited awareness among clinicians 6
• Patients may report that cannabis helps relieve their symptoms, leading to continued use and worsening of the underlying condition 6
• Many patients remain uncertain about the role of cannabis in their symptoms and may attribute them to other factors like food, alcohol, or stress 6
• Conventional antiemetics including antihistamines and serotonin antagonists may have limited effectiveness 3, 8
• The prevalence of CHS is increasing with the rise in cannabis legalization and higher THC concentrations in modern cannabis products 6, 7

Treatment Algorithm

1. Acute phase (in ED or acute care setting):

   • Apply topical capsaicin 0.1% to abdomen 2, 1
   • Consider haloperidol or olanzapine for severe symptoms 2, 3
   • Provide IV hydration as needed 5, 7
   • Encourage hot showers/baths for temporary relief 1, 5
   • Avoid opioids 2, 1

2. Maintenance phase:

   • Counsel on complete cannabis cessation 1, 5
   • Initiate amitriptyline 25 mg at bedtime, titrating weekly to 75-100 mg 2, 1
   • Monitor for symptom resolution and provide ongoing support 1, 6