Loperamide

# Loperamide ## Overview - **Classification**: Antidiarrheal, opioid receptor agonist - **Mechanism**: Binds to opioid receptors in the gut wall, slowing intestinal motility and increasing water/electrolyte absorption. ## Primary Indications 1. **Acute Diarrhea** - Symptomatic control of non-infectious diarrhea. 2. **Chronic Diarrhea** - Control in conditions like IBS-D or inflammatory bowel disease. 3. **Traveler's Diarrhea** - Adjunctive therapy, often with antibiotics if bacterial. 4. **Ileostomy Output** - Reduction of volume in patients with ileostomies. ## Adult Dosing ### Standard Dosing **Acute Diarrhea (Non-specific)** - **Dose**: **4 mg** initial, then **2 mg** after each loose stool - **Frequency**: As needed - **Route**: Oral - **Maximum**: **8 mg/day** (OTC), **16 mg/day** (Rx under medical supervision) **Chronic Diarrhea / Ileostomy** - **Dose**: **2-4 mg** - **Frequency**: 1-4 times daily - **Route**: Oral - **Duration**: Titrate to control symptoms; use lowest effective dose. - **Maximum**: **16 mg/day** ### Dose Adjustments - **Renal Impairment**: No specific adjustment needed. - **Hepatic Impairment**: Use with **caution**. Monitor for CNS toxicity due to reduced first-pass metabolism. - **Elderly Patients**: No specific dose adjustment needed. Monitor closely for dehydration and electrolyte imbalances. ## Pediatric Dosing ### Neonates (0-28 days) - **Contraindicated**. High risk of paralytic ileus and severe CNS depression. ### Infants (1-12 months) - **Contraindicated**. High risk of paralytic ileus, CNS depression, and toxic megacolon (especially with bacterial enteritis). ### Children (1-5 years) - **Acute Diarrhea**: **Generally not recommended** for routine use. Use only under strict medical supervision if benefits outweigh risks. - **Dose (if prescribed)**: **1 mg** (for children 2-5 years) - **Frequency**: 3 times daily - **Maximum**: **3 mg/day** or **0.1 mg/kg/day** (whichever is lower). - **Special Notes**: High risk of severe adverse effects. Oral solution (1 mg/5 mL) often used for precise dosing. ### Children (6-12 years) - **Acute Diarrhea** - **Dose**: **2 mg** initial, then **1 mg** after each loose stool - **Frequency**: As needed - **Maximum**: **6 mg/day** (6-8 years), **8 mg/day** (9-11 years), **12 mg/day** (12 years). Max dose should not exceed **0.1 mg/kg/day**. ### Adolescents (13-18 years) - **Dose**: Follow **adult dosing** guidelines. - **Maximum**: **8 mg/day** (OTC), **16 mg/day** (Rx under supervision). ## Safety Information ### Contraindications - **Absolute**: Children < 2 years of age. - **Absolute**: Acute dysentery (bloody stools, high fever). - **Absolute**: Bacterial enterocolitis (e.g., *C. difficile*, *Salmonella*, *Shigella*). - **Absolute**: Abdominal pain without diarrhea. - **Absolute**: Conditions where constipation must be avoided (e.g., ileus, severe constipation). - **Absolute**: Known hypersensitivity to loperamide. ### Common Adverse Effects - **Common (1-10%)**: Constipation, abdominal cramps, nausea, dizziness, dry mouth. - **Less Common (0.1-1%)**: Headache, fatigue, vomiting, rash. - **Serious but Rare**: Ileus, toxic megacolon, QT prolongation/Torsades de Pointes (especially with high doses/abuse), CNS depression (particularly in children), serious skin reactions (e.g., SJS, TEN). ### Key Drug Interactions - **CYP3A4/2C8 Inhibitors (e.g., Ketoconazole, Ritonavir, Quinidine, Gemfibrozil)**: May increase loperamide plasma levels. Monitor for CNS depression. - **P-glycoprotein Inhibitors (e.g., Quinidine, Ritonavir, Itraconazole)**: Can increase loperamide absorption/exposure. - **Opioids/CNS Depressants**: Additive CNS depression. Avoid or use with extreme caution. ## Monitoring & Follow-up - **Before Treatment**: Rule out underlying infectious or inflammatory causes of diarrhea. - **During Treatment**: Monitor for abdominal distension, constipation, and signs of ileus. - **Clinical Signs**: Discontinue if abdominal distension, constipation, or ileus occurs. If acute diarrhea persists >48 hours, re-evaluate patient. ## Clinical Pearls - 💡 **Not for routine pediatric use**: High risk of serious adverse effects in children <6 years; use with extreme caution if at all. - 💡 **Abuse potential**: Misuse of high doses can lead to cardiac toxicity (QT prolongation) and opioid-like effects. Adhere strictly to recommended doses. - 💡 **Hydration is key**: Loperamide manages symptoms; oral rehydration therapy (ORT) is crucial, especially in children and elderly. - 💡 **Discontinue if no improvement**: If diarrhea doesn't improve within 48 hours for acute cases, seek medical re-evaluation. > **⚠️ Important**: This information is for educational purposes only. Always consult current prescribing information, local guidelines, and clinical judgment before prescribing.