How to treat vomiting?

Treatment of Vomiting

The most effective approach to treating vomiting is to identify and address the underlying cause while using dopamine receptor antagonists such as metoclopramide, haloperidol, or prochlorperazine as first-line antiemetic therapy for symptomatic relief. 1

Initial Assessment and Management

• Identify and treat underlying causes of vomiting, including chemotherapy/radiation-induced vomiting, severe constipation, gastroparesis, bowel obstruction, medication-induced vomiting, and metabolic abnormalities 1
• For gastritis or gastroesophageal reflux-related vomiting, use proton pump inhibitors or H2 receptor antagonists 1
• Ensure adequate hydration and correct any electrolyte abnormalities that may be present 2
• Assess for "red flag" signs such as bilious vomiting, altered mental status, or severe dehydration that may indicate serious underlying conditions requiring urgent intervention 1

Pharmacological Treatment Algorithm

First-Line Therapy

• Dopamine receptor antagonists are recommended as first-line therapy for persistent vomiting 1:
  • Metoclopramide 5-10 mg PO/IV three times daily (lower doses in elderly patients) 1, 3
  • Haloperidol 0.5-2 mg PO/IV every 4-6 hours 1
  • Prochlorperazine 5-10 mg PO/IV every 6-8 hours 1

Second-Line Therapy

• If vomiting persists, add one of the following 2, 1:
  • 5-HT3 receptor antagonists such as ondansetron 4-8 mg PO/IV 2-3 times daily 1, 4
  • Granisetron 1 mg PO twice daily or 34.3 mg transdermal patch weekly 1
  • Olanzapine 2.5-5 mg PO daily (especially effective in palliative care settings) 1, 3

For Anxiety-Related Nausea and Vomiting

• Consider adding benzodiazepines such as lorazepam 0.5-1 mg PO/IV every 4-6 hours 2, 1

For Refractory Symptoms

• Consider adding corticosteroids such as dexamethasone 4-8 mg PO/IV daily 2, 1
• For severe, persistent vomiting, consider continuous IV or subcutaneous infusion of antiemetics 1
• Cannabinoids (dronabinol, nabilone) may be used when conventional antiemetics fail 2

Special Considerations

Chemotherapy-Induced Vomiting

• Follow specific antiemesis guidelines based on the emetogenic potential of the chemotherapy regimen 2
• For highly emetogenic chemotherapy, a combination of 5-HT3 antagonist, dexamethasone, and aprepitant is recommended 2
• For breakthrough chemotherapy-induced vomiting, add an agent from a different drug class to the current regimen 2

Radiation-Induced Vomiting

• For total body irradiation or upper abdominal radiation, prophylactic antiemetics are recommended 2
• 5-HT3 antagonists such as ondansetron have shown efficacy in preventing radiation-induced vomiting 2

Pediatric Considerations

• Ondansetron (0.15-0.2 mg/kg) is particularly effective for children with persistent vomiting 5, 6
• Avoid antiemetics with significant sedative effects in children 5

Elderly Patients

• Use lower starting doses of antiemetics in elderly patients 3
• Monitor closely for extrapyramidal side effects with dopamine antagonists 1, 3
• Avoid long-term use of benzodiazepines due to risk of dependence 3

Important Pitfalls to Avoid

• Do not use antiemetics in patients with suspected mechanical bowel obstruction without surgical consultation 1
• Avoid metoclopramide in patients with Parkinson's disease or history of tardive dyskinesia 1
• Be aware that ondansetron can prolong the QT interval, especially in patients with electrolyte abnormalities or cardiac disease 4
• For patients with vomiting due to acute gastroenteritis, focus on oral rehydration therapy rather than rushing to antiemetic use 7, 5
• When using combination therapy, target different mechanisms of action for synergistic effect rather than replacing one antiemetic with another 1

Non-Pharmacological Management

• For mild vomiting, consider small, frequent meals and avoiding trigger foods 8
• Ensure adequate fluid intake to prevent dehydration 2, 1
• For anxiety-related vomiting, relaxation techniques may be beneficial as an adjunct to medication 1