What are the routes of administration and dosing guidelines for prochlorperazine?

Prochlorperazine Administration Routes and Dosing

Prochlorperazine can be administered via oral, intramuscular (IM), intravenous (IV), or rectal suppository routes, with dosing ranging from 5-10 mg orally/IV every 4-6 hours for nausea/vomiting to 10-20 mg IM for acute psychiatric symptoms, not exceeding 40 mg total daily dose by any parenteral route. 1

Routes of Administration

Oral Route

• Standard dosing: 10 mg orally every 6 hours as needed for short-term management of nausea, vomiting, or dizziness 2
• For chemotherapy-induced nausea/vomiting: 10-20 mg orally 3-4 times daily 3
• Alternative dosing: 10 mg every 4-6 hours 4

Intramuscular (IM) Route

• Inject deeply into the upper, outer quadrant of the buttock 1
• Never use subcutaneous administration due to risk of local irritation 1
• For nausea/vomiting: Initially 5-10 mg IM, repeat every 3-4 hours if necessary 1
• For acute psychiatric symptoms: 10-20 mg IM every 2-4 hours initially for control, then every 4-6 hours for maintenance 1
• Maximum total IM dosage: 40 mg per day 1

Intravenous (IV) Route

• Administer as slow IV injection at a rate not exceeding 5 mg per minute 1
• Never use bolus injection due to hypotension risk 1
• For nausea/vomiting: 2.5-10 mg by slow IV injection or infusion 1
• Can be given undiluted or diluted in isotonic solution 1
• Single dose should not exceed 10 mg; total IV dosage should not exceed 40 mg per day 1
• In emergency settings, 2.5 mg IV has been shown effective for acute myocardial infarction-related nausea 5

Rectal Suppository Route

• 25 mg suppository every 12 hours for breakthrough chemotherapy-induced nausea/vomiting 4
• Also recommended for cyclic vomiting syndrome episodes 4

Special Population Dosing

Elderly Patients

• Use lower range dosages as elderly patients are more susceptible to hypotension and neuromuscular reactions 1
• Increase dosage more gradually and monitor closely 1

Pediatric Patients

• Do NOT use in children under 20 pounds or under 2 years of age 1
• Do NOT use in pediatric surgery due to increased risk of extrapyramidal reactions 1
• For severe nausea/vomiting: Calculate 0.06 mg per pound of body weight by deep IM injection 1
• Children are more prone to extrapyramidal reactions even on moderate doses 1

Debilitated or Emaciated Patients

• Increase dosage more gradually 1
• Begin with lowest recommended dosage 1

Critical Safety Considerations

Cardiovascular Monitoring

• Hypotension is a significant risk with IV administration 1
• Repeated doses can prolong QT interval and potentially precipitate torsades de pointes 3, 4

Extrapyramidal Symptoms

• Monitor for dystonic reactions, particularly akathisia which can occur within one week 6
• Have diphenhydramine 25-50 mg PO or IV available for dystonic reactions 4
• Extrapyramidal symptoms occur in approximately 14% of patients 6

Other Adverse Effects

• Anticholinergic effects including dry mouth 2, 4
• CNS depression and sedation (38% incidence) 4, 7
• Tachycardia 2

Clinical Pearls for Refractory Symptoms

When Prochlorperazine Fails

• Add a 5-HT3 receptor antagonist (ondansetron or granisetron) for enhanced effect 2, 4
• Consider adding dexamethasone in chemotherapy settings 2, 4
• Alternative agents include metoclopramide 10-40 mg every 4-6 hours or promethazine 12.5-25 mg every 4 hours 4

Comparative Efficacy

• Prochlorperazine 10 mg IV is superior to promethazine 25 mg IV for ED nausea/vomiting, with faster relief and fewer treatment failures (9.5% vs 31%) 7
• Prochlorperazine causes significantly less sedation than promethazine (38% vs 71%) 7

Contraindications and Cautions

• Use with caution in patients with leukopenia, neutropenia, dementia, glaucoma, or seizure disorders 4
• Protect solution from light; discard if markedly discolored 1
• Do not mix with other agents in the syringe 1