What is the dose for hyperemesis (excessive vomiting) related to marijuana, or cannabinoid hyperemesis syndrome (CHS)?

Haloperidol Dosing for Cannabis Hyperemesis Syndrome

For acute cannabis hyperemesis syndrome, use haloperidol as the first-line antiemetic agent, as it demonstrates superior efficacy by reducing hospital length of stay by nearly 50% compared to conventional antiemetics (6.7 vs 13.9 hours, p=0.014). 1

Acute Management Algorithm

First-Line Pharmacologic Treatment

• Haloperidol is the preferred butyrophenone for acute CHS management due to its documented superiority in reducing symptom duration and hospital stay 1
• Alternative butyrophenone: Droperidol can be used if haloperidol is unavailable 1, 2
• These antipsychotics are more effective than traditional antiemetics like ondansetron, which typically shows limited efficacy in CHS 3, 4

Adjunctive Therapies to Combine with Haloperidol

• Topical capsaicin 0.1% applied to the abdomen activates TRPV1 receptors and provides consistent symptom relief 3, 1, 4
• Benzodiazepines address the stress-mediated component through sedating and anxiolytic effects, with documented case series showing resolution of symptoms when conventional antiemetics failed 1, 5, 2
• Hot water hydrotherapy (hot showers/baths) provides temporary symptomatic relief and serves as a diagnostic clue, with 44-71% of CHS patients exhibiting this pathognomonic behavior 3, 1, 2

What NOT to Use

• Avoid opioids entirely as they worsen nausea, carry high addiction risk, and do not address the underlying pathophysiology 3, 1, 4
• Ondansetron may be tried but expect limited efficacy compared to its use in other conditions 3, 6

Multimodal Antiemetic Protocol

The British Journal of Anaesthesia and American Gastroenterological Association recommend a multimodal approach that differs from standard PONV protocols 1:

• Prioritize butyrophenones (haloperidol or droperidol) as the foundation
• Add benzodiazepines for anxiolysis and sedation
• Apply topical capsaicin 0.1% to the abdomen
• Encourage hot water bathing for immediate symptomatic relief

Critical Diagnostic Confirmation

Before initiating treatment, confirm CHS diagnosis based on 3, 1:

• Regular cannabis use >4 times weekly for >1 year
• Stereotypical episodic vomiting (≥3 episodes annually)
• Compulsive hot water bathing behavior (present in 44-71% of cases)
• Rule out life-threatening conditions first: acute abdomen, bowel obstruction, mesenteric ischemia, pancreatitis, myocardial infarction 3, 1

Definitive Treatment

Cannabis cessation is the only definitive treatment and must be strongly emphasized, as it is the only intervention leading to long-term resolution 3, 1, 4, 7:

• Symptoms resolve after abstinence for at least 6 months or duration equal to 3 typical vomiting cycles 3
• 96.8% of patients experience complete resolution with cannabis cessation 7

Long-Term Preventive Management

For patients who achieve cannabis cessation 3, 1:

• Tricyclic antidepressants (amitriptyline) are the mainstay: start 25 mg at bedtime, titrate weekly to reach minimal effective dose of 75-100 mg
• Provide cannabis cessation counseling as essential component
• Consider psychological support for anxiety and depression comorbidities
• Co-manage with psychiatry for extensive psychiatric comorbidity or treatment resistance

Common Pitfalls to Avoid

• CHS is frequently underdiagnosed due to limited clinician awareness, leading to extensive unnecessary testing 1, 4, 8
• Do not rely on conventional antiemetics (ondansetron, metoclopramide) as primary therapy—they typically fail in CHS 3, 4
• Do not prescribe opioids, which worsen the condition 3, 1
• Diagnostic delay averages several years when clinicians fail to ask directed questions about cannabis use and hot water bathing behavior 8