Usual Dose of Rectal Prochlorperazine
The usual dose of rectal prochlorperazine is 25 mg suppository every 12 hours for breakthrough nausea and vomiting. 1
Dosing Guidelines by Indication
Chemotherapy-Induced Nausea and Vomiting
- For breakthrough treatment of chemotherapy-induced nausea/vomiting: 25 mg suppository PR every 12 hours 1
- Alternative oral/IV dosing: 10 mg PO or IV every 4-6 hours 1
- May be used as part of low emetic risk chemotherapy regimens 1
Migraine Treatment
- 25 mg rectal suppository provides effective pain relief within 2 hours for acute migraines 2
- Studies show excellent efficacy with rectal administration for migraine-related nausea 2
- All patients in controlled studies experienced positive treatment outcomes with rectal prochlorperazine for migraine 2
Cyclic Vomiting Syndrome
- 5-10 mg every 6-8 hours orally; 25 mg suppository every 12 hours during episodes 1
- Used as an abortive therapy for moderate to severe cyclic vomiting episodes 1
Administration Considerations
Safety Profile
- Monitor for dystonic reactions; use diphenhydramine 25-50 mg PO or IV every 4-6 hours for dystonic reactions 1
- Akathisia is a common side effect with IV administration (44% incidence within 1 hour of IV administration) but less common with rectal administration 3
- Rectal administration has shown no significant adverse reactions in controlled studies 2
Contraindications and Precautions
- Use with caution in patients with history of leukopenia or neutropenia, dementia, glaucoma, or seizure disorder 1
- Repeated doses can prolong QT interval and potentially precipitate torsades de pointes 4
- CNS depression, anticholinergic effects, and extrapyramidal symptoms are potential adverse effects 1
Clinical Pearls
- Rectal administration is particularly useful when oral intake is not possible due to severe nausea or vomiting 2
- For patients with persistent nausea despite prochlorperazine, consider adding a serotonin antagonist such as ondansetron or granisetron 4
- In chemotherapy settings, a combination approach with dexamethasone may provide enhanced efficacy 4
- Low-dose IV administration (2.5 mg) has shown rapid efficacy for emergency control of vomiting with mean time to cessation of 8.5 minutes 5
Alternative Antiemetics When Prochlorperazine Is Ineffective
- Metoclopramide: 10-40 mg PO or IV every 4-6 hours 1
- Ondansetron: 16 mg PO or 8 mg IV daily 1
- Promethazine: 12.5-25 mg PO or IV every 4 hours 1
Remember that prochlorperazine is significantly more effective than promethazine for relieving symptoms of nausea and vomiting more quickly and completely in emergency department patients 6.