Antipsychotic Medications and Nausea Management in Palliative Care

Introduction to Antipsychotic Mechanism

Antipsychotic phenothiazine has a broader receptor profile than chlorpromazine, with some analgesic effect, unique among typical antipsychotics 1

Antipsychotic phenothiazine is used for sedation in palliative care and for management of agitation in emergency settings, including delirium, supported by guidelines 1, 2

The starting dose for sedation in palliative care is 12.5 mg IV/IM every 4-12 hours, or 3-5 mg/h IV, or 25-100 mg rectally every 4-12 hours, with a usual effective dose of parenteral 37.5-150 mg/day, rectal 75-300 mg/day 1
For palliative sedation, the starting dose can be 12.5-25 mg or 50-75 mg continuous infusion, with a usual effective dose of 12.5 or 25 mg every 8 hours and every 1 hour PRN for breakthrough agitation, or up to 300 mg/day continuous infusion 1

Chlorpromazine can be administered orally, IV, IM, or rectally, while levomepromazine can be administered orally, IV, SC, or IM 1
Both medications can cause significant sedation and hypotension, requiring careful monitoring, especially in elderly patients or those with cardiovascular disease 1

For acute agitation in delirium, either antipsychotic phenothiazine or levomepromazine can be effective, but levomepromazine may be preferred when analgesia is also needed 1
For palliative sedation, both are effective options, with dosing tailored to symptom severity 1

The National Comprehensive Cancer Network recommends using around-the-clock dosing rather than PRN for effective management of nausea and vomiting 3
The National Comprehensive Cancer Network suggests considering IV or rectal routes when oral administration is not feasible due to vomiting 3
Dexamethasone is recommended for CNS involvement (brain, meninges) with a dosage of 4-8 mg tid-qid, providing a dual benefit of antiemetic effect and reduction of intracranial pressure, with a strength of evidence of high 4, 5
Ondansetron, a 5-HT3 antagonist, is highly effective for persistent nausea and vomiting, and should be administered around-the-clock rather than PRN, at a dose of 8mg IV/PO every 8 hours, as recommended by the National Comprehensive Cancer Network, with a strength of evidence of high 6, 5
Other antiemetic options include:

Behavioral therapies such as progressive muscle relaxation, systematic desensitization, and hypnosis can be effective but may be difficult to implement in acute settings, according to the European Society for Medical Oncology 8
Dietary modifications, such as taking small bites, chewing thoroughly, eating slowly, separating liquids from solids, and spacing meals at intervals of ≥2-4 hours, can help manage nausea and vomiting, with a strength of evidence of moderate 9, 4, 5, 10
Ensuring adequate fluid intake (≥1.5L/day) with varied temperatures and flavors is important for hydration, as recommended by the National Comprehensive Cancer Network, with a strength of evidence of high 9
Critical lifestyle changes, including weight management if overweight/obese, avoiding trigger foods, and smoking cessation if applicable, are recommended, with a strength of evidence of high 11

Monitor hydration and electrolytes closely, as dehydration and electrolyte abnormalities can occur, with a strength of evidence of high 9
Assess for signs of increased intracranial pressure, such as headache and altered mental status, as recommended by the National Comprehensive Cancer Network 4
Monitor for seizures, which may occur post-treatment, and consider prophylactic antiepileptic drugs if seizures occur, with a strength of evidence of moderate 12
Endoscopic evaluation is necessary for persistent nausea and vomiting, particularly when alarm features are present, with a strong recommendation based on high-quality evidence, supported by the National Comprehensive Cancer Network and American Gastroenterological Association 13
Daily evaluation of vomiting frequency and characteristics, monitoring hydration and electrolyte levels, and adjusting the antiemetic regimen according to patient response are crucial, with a strength of evidence of high 3, 4

The presence of a worm in vomit strongly suggests a parasitic gastrointestinal infection, requiring urgent endoscopic evaluation for direct visualization, identification, and treatment to prevent further complications, as recommended by the American Gastroenterological Association 14
Consider thiamin supplementation if vomiting persists >2-3 weeks to prevent neurological complications, with a strength of evidence of low 9