What is the role of Perinorm (metoclopramide) in managing vomiting?

Metoclopramide (Perinorm) in Managing Vomiting

Metoclopramide is recommended as a first-line therapeutic agent for managing vomiting, particularly for nausea and vomiting associated with gastroparesis, chemotherapy, and other conditions where gastric emptying is delayed. 1, 2

Mechanism of Action

• Metoclopramide acts as a dopamine receptor antagonist in the central nervous system, blocking stimulation of the chemoreceptor trigger zone (CTZ) which produces antiemetic effects 2, 3
• It increases gastric motility by enhancing the tone and amplitude of gastric contractions, relaxing the pyloric sphincter, and increasing peristalsis of the duodenum and jejunum, resulting in accelerated gastric emptying 2, 4
• It increases lower esophageal sphincter pressure, which helps reduce reflux-related nausea and vomiting 2, 3

Clinical Applications

First-line Use

• Recommended as first-line therapy for persistent vomiting, particularly when associated with gastroparesis 1, 5
• Effective for chemotherapy-induced nausea and vomiting, especially when used in combination with other antiemetics 1
• Useful for postoperative nausea and vomiting 3, 4

Dosing

• Standard oral dosing: 10 mg three times daily before meals and at bedtime 1, 2
• For breakthrough vomiting: 10-20 mg PO/IV every 4-6 hours 1
• Duration: Not intended for long-term use; oral preparations recommended for 4-12 weeks maximum, parenteral use limited to 1-2 days 3

Efficacy in Specific Conditions

• Gastroparesis: First-line agent for medically refractory gastroparesis with persistent nausea and vomiting 1
• Chemotherapy-induced nausea/vomiting: Effective when used as part of multimodal antiemetic regimens 1
• Breakthrough vomiting: Listed as a treatment option for breakthrough nausea and vomiting in patients receiving chemotherapy 1
• Radiation-induced nausea/vomiting: May be appropriate as monotherapy, particularly in patients with nausea and vomiting 1

Adverse Effects and Precautions

• Common side effects: Restlessness, drowsiness, fatigue, and lassitude 2, 3

• Serious concerns:

  • Tardive dyskinesia risk increases with prolonged use (>12 weeks) and higher doses 2
  • Extrapyramidal symptoms can occur, especially with high doses or prolonged use 2, 4
  • Black box warning for tardive dyskinesia, though risk may be lower than previously estimated 1

• Monitoring: Patients should be monitored for extrapyramidal side effects 5, 2

• Contraindications: Not recommended in patients with mechanical bowel obstruction, pheochromocytoma, or seizure disorders 2, 6

Important Clinical Considerations

• Metoclopramide should not be used for more than 12 weeks due to risk of tardive dyskinesia 2, 3
• In rare cases, even short-term, low-dose treatment can cause long-lasting adverse effects 7
• For chemotherapy-induced nausea and vomiting, metoclopramide is often used as part of a multimodal regimen rather than as monotherapy 1
• When used for breakthrough vomiting, adding one agent from a different drug class to the current regimen is recommended 1

Algorithm for Vomiting Management

1. First step: Identify and treat underlying causes of vomiting (gastroparesis, chemotherapy, radiation, constipation, medications) 5
2. Initial therapy: Start metoclopramide 10 mg three times daily before meals 1, 2
3. If inadequate response after 4 weeks: Consider:
   • Increasing dose to maximum benefit and tolerance 5
   • Adding 5-HT3 receptor antagonists (ondansetron, granisetron) 1, 5
4. For refractory symptoms: Consider adding olanzapine, which has shown superior efficacy compared to metoclopramide for breakthrough vomiting in some studies 1
5. For anxiety-related nausea: Add benzodiazepines such as lorazepam 1, 5

Metoclopramide remains a valuable antiemetic option due to its dual central and peripheral effects, but careful attention to dosing duration and monitoring for adverse effects is essential for safe use 2, 4.