What is the recommended dosage of prochlorperazine for nausea and vomiting or antipsychotic effects?

Recommended Dosage of Prochlorperazine for Nausea/Vomiting and Antipsychotic Effects

For nausea and vomiting, the standard recommended dosage of prochlorperazine is 10 mg orally every 4-6 hours as needed, with a maximum daily dose of 40 mg for adults. 1

Dosage for Nausea and Vomiting

Adults:

• Oral tablets: 5-10 mg 3-4 times daily, not to exceed 40 mg daily in resistant cases 2
• Suppository: 25 mg every 12 hours as breakthrough treatment 1
• Intravenous: 10 mg every 4-6 hours as needed 1

Children (based on weight):

• Not recommended for children under 20 pounds or under 2 years of age 2
• 20-29 lbs: 2.5 mg 1-2 times daily (maximum 7.5 mg/day) 2
• 30-39 lbs: 2.5 mg 2-3 times daily (maximum 10 mg/day) 2
• 40-85 lbs: 2.5 mg 3 times daily or 5 mg twice daily (maximum 15 mg/day) 2

Dosage for Antipsychotic Effects

Adults:

• Non-psychotic anxiety: 5 mg 3-4 times daily, not to exceed 20 mg per day or for longer than 12 weeks 2
• Psychotic disorders/schizophrenia:
  • Mild conditions: 5-10 mg 3-4 times daily 2
  • Moderate to severe conditions: Starting at 10 mg 3-4 times daily, increasing gradually 2
  • Most patients respond to 50-75 mg daily 2
  • Optimum dosage for severe disturbances: 100-150 mg daily 2

Children with schizophrenia:

• Ages 2-5 years: Starting at 2.5 mg 2-3 times daily, not to exceed 20 mg total daily 2
• Ages 6-12 years: Starting at 2.5 mg 2-3 times daily, not to exceed 25 mg total daily 2
• Do not give more than 10 mg on the first day 2

Clinical Considerations

Efficacy:

• Prochlorperazine works significantly better and faster than promethazine for relieving nausea and vomiting in emergency department settings 3
• Buccal administration achieves higher plasma concentrations and faster onset of action compared to oral administration 4, 5

Special Populations:

• Elderly patients: Use lower doses and monitor closely for hypotension and neuromuscular reactions 2
• Debilitated or emaciated patients: Increase dosage more gradually 2

Chemotherapy-Induced Nausea and Vomiting:

• Recommended for low to moderate emetogenic potential chemotherapy 1
• For highly emetogenic chemotherapy, prochlorperazine alone is insufficient and should be combined with other antiemetics 6

Potential Adverse Effects and Monitoring

• Monitor for extrapyramidal symptoms, particularly akathisia, which may occur within a week of starting treatment 7
• Repeated doses can potentially prolong QT interval 8
• Consider alternative antiemetics like atypical antipsychotics for patients at risk of extrapyramidal symptoms 7

Treatment Algorithm for Nausea and Vomiting

1. First-line for mild to moderate nausea: Prochlorperazine 10 mg PO every 4-6 hours as needed 1
2. For persistent symptoms:
   • Add a serotonin antagonist (ondansetron, granisetron) 6, 8
   • Consider adding dexamethasone 12 mg daily for synergistic effect 1, 6
3. For highly emetogenic chemotherapy: Use combination therapy with 5-HT3 antagonists and dexamethasone as first-line 6

Remember that prochlorperazine should be used with caution in elderly patients and those with cardiovascular disease due to potential hypotensive effects 6.