What antipsychotics are recommended for outpatient management of Cannabinoid Hyperemesis Syndrome (CHS)?

Outpatient Antipsychotics for Cannabinoid Hyperemesis Syndrome

Haloperidol is the recommended first-line antipsychotic for outpatient management of Cannabinoid Hyperemesis Syndrome (CHS), with olanzapine as an effective alternative option. 1, 2

First-Line Management Approach

1. Complete cannabis cessation is the cornerstone and only truly effective long-term treatment for CHS 3

   • Patients should be counseled that symptoms typically require complete abstinence for at least 6 months or duration equal to 3 typical vomiting cycles

2. First-line pharmacologic options for acute symptom management:

   • Haloperidol: Most evidence supports its use in outpatient setting 1
   • Olanzapine: Effective in treatment-refractory cases 2
   • Topical capsaicin (0.1%) applied to the abdomen 3, 4

3. Non-pharmacologic interventions:

   • Hot showers/baths (universally effective for temporary relief) 3, 5
   • Adequate hydration with electrolyte-rich fluids

Antipsychotic Selection and Dosing

Haloperidol

• Preferred first-line antipsychotic for outpatient management 1
• Advantages: Established efficacy in case reports, can be used in outpatient setting
• Starting dose: 0.5-1mg orally, can be titrated as needed
• Monitor for extrapyramidal symptoms

Olanzapine

• Alternative option, particularly effective in treatment-refractory cases 2
• Additional benefit: May be preferred when comorbid psychotic symptoms or agitation are present
• Dosing: Typically 5-10mg orally

Second-Line Options

If antipsychotics are ineffective or contraindicated:

1. Benzodiazepines (e.g., lorazepam) 5, 4

   • Can be effective for short-term symptom relief
   • Caution: Potential for dependence with prolonged use

2. Tricyclic antidepressants (particularly amitriptyline) 3, 5

   • For long-term prevention of episodes
   • Starting at 25mg and titrating to 75-100mg

Important Considerations and Cautions

• Avoid opioids as they can worsen nausea and carry addiction risk 3, 6
• Traditional antiemetics (ondansetron, promethazine, metoclopramide) are often ineffective but may be tried 5, 6
• Monitor for medication side effects, particularly with antipsychotics (extrapyramidal symptoms, sedation)
• Refer patients to addiction specialists for cannabis cessation support 3

When to Escalate Care

Patients should be instructed to seek emergency care if:

• Unable to maintain hydration
• Severe, uncontrolled symptoms despite outpatient management
• Signs of dehydration or electrolyte abnormalities
• Development of concerning symptoms (severe abdominal pain, hematemesis)

Common Pitfalls to Avoid

1. Failing to emphasize cannabis cessation as the definitive treatment
2. Overreliance on traditional antiemetics which are often ineffective in CHS
3. Prescribing opioids which can worsen symptoms and carry addiction risk
4. Not providing adequate follow-up to monitor treatment response and adherence to cannabis cessation

Remember that while pharmacologic interventions can provide symptomatic relief, complete resolution of CHS only occurs with cannabis cessation 3, 5.