A 28-year-old man with migraine-associated nausea and vomiting requires an antiemetic that also enhances gastric motility. Which drug is the preferred choice for this indication?

Explanation

## Antiemetics with Prokinetic Activity **Key Point:** Metoclopramide is the drug of choice for nausea/vomiting associated with migraine because it combines antiemetic action with gastric prokinetic effects, improving drug absorption during migraine attacks. ### Mechanism of Action Metoclopramide is a dopamine antagonist (D2 receptor blocker) that: 1. Blocks chemoreceptor trigger zone → antiemetic effect 2. Enhances acetylcholine effects on gastric smooth muscle → prokinetic effect 3. Increases gastric emptying and intestinal transit ### Why Metoclopramide is Ideal for Migraine-Associated Nausea | Feature | Benefit in Migraine | |---|---| | **Antiemetic** | Controls nausea and vomiting | | **Prokinetic** | Restores gastric motility (migraines slow gastric emptying) | | **Enhances absorption** | Improves bioavailability of concurrent migraine drugs (triptans, NSAIDs) | | **Rapid onset** | Works within 30 minutes (IV/IM) | **High-Yield:** Metoclopramide is specifically recommended in migraine guidelines for nausea because it addresses both the symptom (vomiting) and the underlying gastric dysfunction (delayed emptying). ### Comparison with Other Antiemetics | Drug | Class | Antiemetic | Prokinetic | Use in Migraine | |---|---|---|---|---| | **Metoclopramide** | Dopamine antagonist | ✓ | ✓ | **First-line** | | Granisetron | 5-HT3 antagonist | ✓ | ✗ | Second-line; no gastric benefit | | Domperidone | Dopamine antagonist | ✓ | ✓ | Alternative; poor BBB penetration | | Cyclizine | H1 antagonist | ✓ | ✗ | Not preferred; anticholinergic effects | **Clinical Pearl:** In acute migraine, metoclopramide 10 mg IV/IM is often given alongside triptans to enhance their absorption and control associated nausea simultaneously. **Warning:** Prolonged use (>3 months) carries risk of tardive dyskinesia. For chronic migraine prophylaxis, use should be limited and monitored. **Mnemonic:** **METRO** = **M**etoclopramide for **E**mesis + **T**ransit (prokinetic) in **R**estored **O**utflow (gastric emptying). [cite:KD Tripathi 8e Ch 48; Harrison 21e Ch 379]