What is the management and treatment approach for a patient with a history of long-term cannabis use presenting with cannabis hyperemesis syndrome (CHS)?

Cannabis Hyperemesis Syndrome Management

Definitive Treatment

Cannabis cessation is the only definitive treatment for cannabis hyperemesis syndrome and must be strongly recommended to all patients, with complete symptom resolution requiring at least 6 months of continuous abstinence. 1, 2

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Acute Emergency Department Management

Initial Assessment and Diagnosis

• Rule out life-threatening conditions first before confirming CHS: acute abdomen, bowel obstruction, mesenteric ischemia, pancreatitis, and myocardial infarction 1, 2
• Diagnose CHS based on three required criteria: stereotypical episodic vomiting (≥3 episodes annually), cannabis use >1 year with frequency >4 times weekly, and symptom resolution after 6+ months of abstinence 1, 2
• Look for pathognomonic hot water bathing behavior, present in 44-71% of CHS patients, though this also occurs in cyclic vomiting syndrome and is not diagnostic 1

First-Line Acute Pharmacotherapy

Prioritize butyrophenones (haloperidol or droperidol) as first-line agents, as they reduce hospital length of stay by nearly 50% (6.7 vs 13.9 hours, p=0.014) compared to standard antiemetics. 1, 3

• Droperidol 0.625 mg IV is the most frequently effective dose 3
• Haloperidol is the alternative butyrophenone when droperidol is unavailable 1, 2

Second-Line Acute Agents

• Benzodiazepines (particularly lorazepam) are highly effective for acute nausea and vomiting, addressing the stress-mediated component of CHS 1, 2
• Topical capsaicin 0.1% applied to the abdomen activates TRPV1 receptors and provides consistent benefit 1, 2
• Promethazine or olanzapine can be considered as additional antipsychotic options 1, 2

Medications to Avoid

• Never use opioids as they worsen nausea, carry high addiction risk, and do not address the underlying pathophysiology 1, 2
• Ondansetron has limited efficacy in CHS compared to conventional antiemetic use in other conditions 2

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Long-Term Preventive Management

Pharmacologic Prevention

Tricyclic antidepressants, specifically amitriptyline, are the mainstay of long-term preventive therapy. 1, 2

• Start amitriptyline 25 mg at bedtime 1, 2
• Titrate weekly by 25 mg increments to reach minimal effective dose of 75-100 mg 1, 2

Cannabis Cessation Counseling

• Counsel patients that complete resolution requires at least 6 months of continuous cannabis abstinence, or abstinence duration equal to at least 3 typical vomiting cycles for that specific patient 1, 2, 4
• Inform patients that symptoms will only resolve with complete and sustained cannabis abstinence 1, 2
• Provide psychological support as anxiety and depression are common comorbidities 2
• Consider referral to psychiatry or addiction medicine specialists for co-management, particularly for patients with extensive psychiatric comorbidity or treatment resistance 2, 5

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Critical Diagnostic Pitfalls to Avoid

• Do not pursue exhaustive investigations once CHS is suspected; focus on early diagnosis to facilitate treatment 1
• CHS is frequently underdiagnosed or misdiagnosed due to limited clinician awareness, leading to unnecessary testing 1
• Distinguish CHS from cannabis withdrawal syndrome: vomiting occurs during active cannabis use in CHS versus after stopping in withdrawal syndrome 6

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Special Perioperative Considerations

Preoperative Planning

• Patients with CHS require enhanced prophylactic antiemetic therapy perioperatively due to increased risk for post-anesthesia intractable vomiting 1
• Use multimodal antiemetic prophylaxis that differs from standard PONV protocols, prioritizing butyrophenones and benzodiazepines 1

Anesthetic Management

• Cannabis users may require higher doses of anesthetic agents to achieve adequate depth 1
• Consider processed depth of anesthesia EEG monitoring (BIS) for patients with heavy cannabis use 1

Postoperative Pain Management

• Anticipate higher postoperative analgesic requirements in chronic cannabis users 1
• Use multimodal non-opioid analgesia strategies, avoiding opioids entirely 1

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Managing Cannabis Withdrawal During Treatment

• Approximately 47% of regular cannabis users experience withdrawal syndrome after cessation 6
• Withdrawal symptoms (irritability, anxiety, insomnia, decreased appetite, restlessness, GI symptoms) typically onset within 24-72 hours, peak days 2-6, and resolve within 1-2 weeks 6
• For patients with significant withdrawal symptoms who were consuming high amounts of cannabis (>1.5 g/day inhaled, >20 mg/day THC oil, or >300 mg/day CBD oil), consider nabilone or nabiximols substitution with psychiatry or addiction medicine guidance 6
• Use standard antidiarrheal agents like loperamide for GI distress during withdrawal 6
• Assess for concurrent mental health disorders as anxiety and depressive symptoms may emerge or intensify during withdrawal 6