Recommended Medications for Nausea and Vomiting
First-line medications for nausea and vomiting should be dopaminergic pathway antagonists such as haloperidol, risperidone, metoclopramide, or prochlorperazine, with a second agent like ondansetron added when first-line medications fail to control symptoms. 1
First-Line Antiemetic Options
Dopamine Antagonists
- Haloperidol: 0.5-2 mg orally or IV 3-6 times daily 1
- Prochlorperazine: 5-10 mg orally or IV 3-4 times daily 1
- Metoclopramide: 20-30 mg orally 3-4 times daily 1
- Chlorpromazine: 12.5-25 mg IV or 25-50 mg orally 3-4 times daily 1
These medications work by inhibiting receptors in the brain's chemoreceptor trigger zone and are considered highly effective for general nausea and vomiting 1.
Second-Line Options
When first-line medications fail to adequately control symptoms, add:
- Ondansetron: 8 mg IV or 16-24 mg orally once daily 1, 2
- Other 5-HT3 antagonists: Granisetron (2 mg orally once daily) or Palonosetron (0.25 mg IV once daily) 1, 3
5-HT3 antagonists are particularly effective for chemotherapy-induced and postoperative nausea and vomiting but have not shown superiority to dopaminergic agents for general nausea and vomiting at the end of life 1.
Special Situations
Bowel Obstruction
- Octreotide: Recommended for nausea and vomiting due to bowel obstruction caused by cancer (high recommendation) 1
- Dexamethasone: 2-8 mg orally or IV 3-6 times daily for bowel obstruction 1
Anticipatory Nausea
- Lorazepam: 0.5-2 mg orally or IV 4 times daily 1
Increased Oral Secretions
- Scopolamine: 1.5-3 mg topical patch every 72 hours 1
Route of Administration Considerations
- For actively vomiting patients, use intravenous or subcutaneous routes rather than oral administration 3
- For oral medications, timing is important - administer 30-60 minutes before anticipated nausea triggers when used prophylactically 3
Dosing Adjustments
- Hepatic Impairment: For ondansetron, do not exceed a total daily dose of 8 mg in patients with severe hepatic impairment (Child-Pugh score ≥10) 2
Monitoring and Follow-up
- Establish a clear communication plan between healthcare provider and patient for reporting persistent symptoms 1
- For outpatients, alternative treatment options should be presented within 1 month if symptoms persist 1
- For inpatients, alternative treatment options should be considered within 48 hours if symptoms persist 1
Common Pitfalls to Avoid
QT prolongation risk: Monitor ECG in patients receiving ondansetron who have electrolyte abnormalities, congestive heart failure, or bradyarrhythmias 2
Extrapyramidal symptoms: Monitor for akathisia with prochlorperazine or metoclopramide, which can develop up to 48 hours after administration 4
Sedation concerns: Be aware that promethazine causes more sedation than other antiemetics - this may be desirable in some situations but problematic in others 4
Vascular damage: Exercise caution with IV administration of promethazine due to potential for vascular damage 4
Overlooking underlying causes: Always consider other causes of nausea and vomiting (radiotherapy, infection, metabolic disorders, electrolyte disturbances, constipation, gastrointestinal obstruction, brain metastases) 1, 5
By following this algorithmic approach to antiemetic selection based on symptom severity and specific clinical situations, most cases of nausea and vomiting can be effectively managed while minimizing adverse effects.