Metoclopramide

# Metoclopramide ## Overview - **Classification**: Antiemetic, Prokinetic - **Mechanism**: Dopamine D2 receptor antagonist (central & peripheral); enhances acetylcholine release to promote gastric motility and emptying. ## Primary Indications 1. **Nausea and Vomiting** - Associated with chemotherapy, surgery, or gastroparesis. 2. **Diabetic Gastroparesis** - Symptomatic relief of acute and recurrent diabetic gastroparesis. 3. **Gastroesophageal Reflux Disease (GERD)** - Short-term, for patients refractory to conventional therapy. ## Adult Dosing ### Standard Dosing **Diabetic Gastroparesis** - **Dose**: **10 mg** - **Frequency**: 30 minutes before meals and at bedtime (QID) - **Route**: Oral - **Duration**: Up to 4-12 weeks - **Maximum**: **40 mg/day** **Chemotherapy-Induced Nausea/Vomiting (CINV) - High Dose** - **Dose**: **1-2 mg/kg** - **Frequency**: Every **2-4 hours** (for up to 5 doses) - **Route**: IV (infuse over 15-30 minutes) - **Maximum**: **2 mg/kg/dose** **Postoperative Nausea/Vomiting (PONV)** - **Dose**: **10-20 mg** - **Frequency**: Every **4-6 hours** as needed - **Route**: IM or IV (infuse over 1-2 minutes) ### Dose Adjustments - **Renal Impairment**: - CrCl < 40 mL/min: Reduce dose by **50%**. - CrCl < 10 mL/min: Reduce dose by **75%**. - **Hepatic Impairment**: No specific dose adjustment; monitor closely for adverse effects. - **Elderly Patients**: Start at lower end of dosing range (e.g., **5 mg**). Increased risk of extrapyramidal symptoms (EPS). ## Pediatric Dosing *Note: Due to risk of tardive dyskinesia (TD) and EPS, use only when benefits outweigh risks. Limit duration to < 12 weeks.* ### Neonates (0-28 days) - **Dose**: **0.05-0.1 mg/kg/dose** - **Frequency**: Every **6-8 hours** - **Maximum**: **0.5 mg/kg/day** - **Special Notes**: Use with extreme caution. Not routinely recommended due to high risk of EPS. ### Infants (1-12 months) - **Dose**: **0.1 mg/kg/dose** - **Frequency**: Every **6-8 hours** - **Maximum**: **0.5 mg/kg/day** (or **10 mg/dose**) ### Children (1-12 years) - **Dose**: **0.1 mg/kg/dose** - **Frequency**: Every **6-8 hours** - **Maximum**: **0.5 mg/kg/day** (or **10 mg/dose** up to adult maximum **40 mg/day**) ### Adolescents (13-18 years) - **Dose**: Use adult dosing range of **5-10 mg** - **Frequency**: Every **6-8 hours** as needed or **30 mins before meals and at bedtime** - **Maximum**: **40 mg/day** ## Safety Information ### Contraindications - **Absolute**: Gastrointestinal obstruction, perforation, hemorrhage - **Absolute**: Pheochromocytoma (risk of hypertensive crisis) - **Absolute**: Seizure disorder (lowers seizure threshold) - **Absolute**: History of metoclopramide-induced tardive dyskinesia - **Absolute**: Parkinson's disease (worsens symptoms) - **Absolute**: Concomitant use with other agents likely to cause EPS ### Common Adverse Effects - **Very Common (>10%)**: Drowsiness, fatigue, restlessness, headache, EPS (especially acute dystonia). - **Common (1-10%)**: Diarrhea, dizziness, anxiety, insomnia. - **Serious but Rare**: Tardive dyskinesia (often irreversible), Neuroleptic Malignant Syndrome (NMS), depression, bradycardia. ### Key Drug Interactions - **CNS Depressants (opioids, alcohol, sedatives)**: Increased sedation; avoid concurrent use. - **Anticholinergics**: Antagonizes prokinetic effect; avoid concurrent use. - **Dopaminergic drugs (levodopa)**: Metoclopramide can antagonize effects; avoid concurrent use. - **Drugs causing EPS (antipsychotics)**: Increased risk of EPS; avoid concurrent use. ## Monitoring & Follow-up - **Before Treatment**: Assess for GI obstruction, seizure history, Parkinson's disease. - **During Treatment**: Monitor for signs of EPS (dystonia, akathisia, parkinsonism), especially within first 24-48 hours. - **Clinical Signs**: Observe for involuntary movements (facial grimacing, tongue protrusion), tremors, restlessness, muscle rigidity, fever. ## Clinical Pearls - 💡 **Black Box Warning**: Risk of tardive dyskinesia with prolonged or high-dose use. Limit duration to **12 weeks**. - 💡 **EPS Management**: Acute dystonic reactions can be treated with IV **diphenhydramine** or **benztropine**. - 💡 **Administration**: Administer oral doses **30 minutes before meals** for optimal effect on gastric emptying. - 💡 **IV Rate**: Administer IV doses slowly over **15-30 minutes** to minimize risk of acute EPS. > **⚠️ Important**: This information is for educational purposes only. Always consult current prescribing information, local guidelines, and clinical judgment before prescribing.