What is the best approach to manage cyclic vomiting syndrome?

Management of Cyclic Vomiting Syndrome

The American Gastroenterological Association recommends amitriptyline 25-150 mg nightly as first-line prophylaxis for moderate-severe CVS (≥4 episodes/year lasting >2 days), combined with immediate abortive therapy using sumatriptan 20 mg intranasal plus ondansetron 8 mg sublingual at the first sign of prodromal symptoms. 1

Disease Severity Classification Determines Treatment Intensity

Before initiating therapy, classify CVS severity to guide your approach 1:

Mild CVS:

• <4 episodes per year
• Each episode lasts <2 days
• No emergency department visits or hospitalizations
• Treatment: Abortive therapy only 1

Moderate-Severe CVS:

• ≥4 episodes per year
• Episodes last >2 days
• Requires ED visits or hospitalizations
• Treatment: Both prophylactic AND abortive therapy 1

Approximately one-third of adults with CVS become disabled, making aggressive treatment essential for moderate-severe disease 1.

Critical First Step: Rule Out Cannabinoid Hyperemesis Syndrome

Screen all patients for cannabis use before confirming CVS diagnosis 1, 2. Cannabis use >4 times weekly for >1 year suggests cannabinoid hyperemesis syndrome (CHS) rather than CVS 1. Require 6 months of cannabis cessation to differentiate between the two conditions 2.

Important caveat: Hot water bathing occurs in 48% of CVS patients who don't use cannabis, so this behavior alone does not distinguish CHS from CVS 2.

Prophylactic Therapy (Inter-Episodic Phase)

First-Line: Amitriptyline

• Start 25 mg at bedtime 1
• Titrate to goal dose of 75-150 mg nightly (1-1.5 mg/kg) 1
• Response rate: 67-75% 1, 2
• Monitor baseline ECG due to QTc prolongation risk 1

Second-Line Options (if amitriptyline fails or is contraindicated):

Topiramate: 1

• Start 25 mg daily
• Titrate to 100-150 mg daily in divided doses
• Monitor electrolytes and renal function twice yearly

Levetiracetam: 1

• Start 500 mg twice daily
• Titrate to 1000-2000 mg daily in divided doses
• Monitor CBC

Zonisamide: 1

• Start 100 mg daily
• Titrate to 200-400 mg daily
• Monitor electrolytes and renal function twice yearly

Aprepitant (adjunctive neurokinin-1 antagonist): 1

• 80 mg 2-3 times weekly for adolescents 40-60 kg
• 125 mg 2-3 times weekly for adolescents >60 kg

Abortive Therapy (Prodromal Phase)

The probability of successfully aborting an episode is highest when medications are taken immediately at the onset of prodromal symptoms 1, 2. Educate patients to recognize their stereotypical prodromal symptoms, which may include 1:

• Impending sense of doom or panic
• Anxiety, restlessness, mental fog
• Fatigue, diaphoresis, flushing
• Headache, bowel urgency

Standard Abortive Regimen:

Sumatriptan 20 mg intranasal spray PLUS Ondansetron 8 mg sublingual 1

• Sumatriptan can be repeated once after 2 hours (maximum 2 doses per 24 hours) 1
• Administer in head-forward position to optimize nasal receptor contact 1
• Ondansetron can be given every 4-6 hours during the episode 1
• Subcutaneous sumatriptan is an alternative route if intranasal is not tolerated 2

Additional Abortive Agents:

Promethazine: 12.5-25 mg oral/rectal every 4-6 hours 1

Prochlorperazine: 5-10 mg every 6-8 hours or 25 mg suppository every 12 hours 1

Sedatives to truncate episodes: 1

• Alprazolam (sublingual or rectal)
• Lorazepam
• Diphenhydramine
• Use caution in adolescents with substance abuse risk

Emergency Department Management (Emetic Phase)

If home abortive therapy fails and the patient enters the emetic phase 1:

Immediate Interventions:

1. Place patient in quiet, dark room to minimize sensory stimulation (patients are often agitated and cannot communicate effectively) 1, 2

2. Aggressive IV fluid replacement with dextrose-containing fluids for rehydration and metabolic support 1, 2

3. Check and correct electrolyte abnormalities immediately 2

4. Ondansetron 8 mg IV every 4-6 hours as first-line antiemetic 1

5. IV ketorolac as first-line non-narcotic analgesia for severe abdominal pain (avoid opioids as they worsen nausea and carry addiction risk) 1, 2

6. IV benzodiazepines for sedation 1, 2

For Refractory Cases:

Use droperidol or haloperidol as dopamine antagonists 1, 2. Multiple concurrent agents with different mechanisms of action may be necessary, administered around-the-clock rather than PRN 2.

Recovery Phase Management

Focus on 2:

• Rehydration with electrolyte-rich fluids (sports drinks)
• Small, frequent sips as tolerated
• Gradual introduction of nutrient drinks

Essential Lifestyle Modifications (All Patients)

1, 2

• Maintain regular sleep schedule (avoid sleep deprivation)
• Avoid prolonged fasting
• Identify and avoid individual triggers
• Implement stress management techniques

Screen and Treat Psychiatric Comorbidities

Screen all patients for anxiety, depression, and panic disorder 1, 2. These conditions are present in 50-60% of CVS patients 1, 2. Treating underlying anxiety can decrease CVS episode frequency 1, 2. Consider referral to psychiatrists, psychologists, or counselors 1.

Common Pitfalls to Avoid

• Missing the prodromal window dramatically reduces abortive therapy effectiveness 1, 2 - educate patients to take medications at the very first prodromal symptom
• Do not misinterpret self-soothing behaviors (excessive water drinking, self-induced vomiting) as malingering - these provide temporary relief and are specific to CVS 2
• Do not overlook retching and nausea - these symptoms are equally disabling as vomiting itself and require aggressive treatment 1, 2
• Do not underestimate disease severity - CVS is disabling and requires aggressive management 2
• Inadequate sedation can worsen symptoms 2

Special Considerations

A personal or family history of migraine (present in 20-30% of patients) supports CVS diagnosis and may guide treatment selection 1, 2. CVS shares many characteristics with migraine and is considered part of the migraine spectrum 3.