What are the first-line and second-line treatments for nausea and vomiting?

First-Line and Second-Line Treatments for Nausea and Vomiting

Dopamine receptor antagonists (such as haloperidol, metoclopramide, and prochlorperazine) are recommended as first-line treatment for nausea and vomiting, while 5-HT3 receptor antagonists (such as ondansetron, granisetron, and palonosetron) are recommended as second-line agents for refractory cases. 1

First-Line Treatments

Dopamine Receptor Antagonists

• Haloperidol: 0.5-2 mg IV/PO every 6-8 hours 1
• Metoclopramide: 10-20 mg PO/IV 3-4 times daily (also has prokinetic effects beneficial for constipation-related nausea) 1
• Prochlorperazine: 5-10 mg PO/IV 3-4 times daily 1
• Dexamethasone: 4-20 mg PO/IV (often used in combination with other antiemetics, particularly for chemotherapy-induced nausea) 2

Administration Strategy

• For routine use, oral administration is recommended 2
• If active nausea and vomiting are present, intravenous administration is preferred 2
• Initially use as-needed dosing, but switch to scheduled around-the-clock administration for at least one week if nausea persists 1

Second-Line Treatments

5-HT3 Receptor Antagonists

• Ondansetron: 4-8 mg IV/PO every 8 hours (standard IV dose is 8 mg) 1, 3
• Granisetron: 1 mg IV or PO daily 1, 2
• Palonosetron: 0.25 mg IV (preferred 5-HT3 antagonist for moderate emetic chemotherapy regimens) 2, 1
• Dolasetron: 100 mg IV (note: use with caution in patients with cardiac conduction issues) 2, 4

Benzodiazepines (for anticipatory nausea)

• Lorazepam: 0.5-2 mg IV/PO every 6 hours 1, 2
• Alprazolam: 0.25-0.5 mg PO three times daily 2

Treatment Algorithms Based on Clinical Context

For General Nausea and Vomiting

1. Start with a dopamine receptor antagonist (metoclopramide, prochlorperazine, or haloperidol) 1
2. If inadequate response, add or switch to a 5-HT3 receptor antagonist (ondansetron, granisetron) 1
3. For persistent symptoms, consider combination therapy with medications from different classes 1

For Chemotherapy-Induced Nausea and Vomiting

1. Highly emetogenic chemotherapy: Three-drug combination of NK1 receptor antagonist (aprepitant/fosaprepitant), 5-HT3 receptor antagonist, and dexamethasone 2
2. Moderately emetogenic chemotherapy: Palonosetron plus dexamethasone 2
3. Low emetogenic chemotherapy: Single antiemetic agent such as dexamethasone, 5-HT3 receptor antagonist, or dopamine receptor antagonist 2
4. Minimal emetogenic chemotherapy: No routine prophylaxis needed 2

For Radiation-Induced Nausea and Vomiting

• For high emetic risk radiation: 5-HT3 antagonist before each fraction plus a 5-day course of dexamethasone 2
• For moderate emetic risk radiation: 5-HT3 antagonist before each fraction (dexamethasone optional) 2

For Anticipatory Nausea and Vomiting

• Lorazepam or alprazolam starting the night before the triggering event 2
• Behavioral techniques such as guided imagery or hypnosis with systematic desensitization 2

Special Considerations

For Refractory Nausea and Vomiting

• Add dopamine antagonists to serotonin antagonists and corticosteroids 2
• Consider rotating to a different agent within the same class 1
• For chemotherapy-induced refractory emesis, consider adding NK1 receptor antagonists if not already included 2

Common Pitfalls to Avoid

• Avoid first-generation antihistamines like diphenhydramine as primary antiemetics as they can exacerbate hypotension, tachycardia, and sedation 1
• 5-HT3 antagonists like ondansetron can cause constipation, which may worsen nausea if not addressed 1
• 5-HT3 antagonists are not effective for delayed nausea and vomiting (occurring 1-2 days after chemotherapy) 5
• Dolasetron should be used with extreme caution in patients who suffer from or may develop prolongation of cardiac conduction intervals 4

By following this evidence-based approach to managing nausea and vomiting, clinicians can effectively control symptoms while minimizing adverse effects and improving patient quality of life.