Urodeoxycholic Acid

# Urodeoxycholic acid ## Overview - **Classification**: Gallstone solubilizing agent, choleretic, cytoprotective agent. - **Mechanism**: Reduces cholesterol saturation of bile, solubilizes gallstones, protects hepatocytes from toxic bile acids, and increases bile flow. ## Primary Indications 1. **Dissolution of cholesterol gallstones**: For small (<20mm), non-calcified stones in a functioning gallbladder. 2. **Primary Biliary Cholangitis (PBC)**: Improves liver function and delays disease progression. 3. **Cholestatic liver diseases**: Including cystic fibrosis-associated liver disease (CFLD). ## Adult Dosing ### Standard Dosing **Dissolution of Cholesterol Gallstones** - **Dose**: **8-10 mg/kg/day** - **Frequency**: Divided **2-3 times daily** - **Route**: Oral - **Duration**: **6-24 months**, with sonographic monitoring. **Primary Biliary Cholangitis (PBC)** - **Dose**: **13-15 mg/kg/day** - **Frequency**: Divided **2-4 times daily** - **Route**: Oral - **Duration**: Long-term, often lifelong. ### Dose Adjustments - **Renal Impairment**: No specific adjustments required. Primarily excreted via bile. - **Hepatic Impairment**: No specific adjustments, as it's used to treat hepatic conditions. Avoid in severe acute cholestasis. - **Elderly Patients**: No specific dose adjustments needed. Monitor for co-morbidities. ## Pediatric Dosing ### Neonates (0-28 days) - **Dose**: **10-15 mg/kg/day** (off-label for cholestasis) - **Frequency**: Divided **2-3 times daily** - **Maximum**: **25 mg/kg/day** - **Special Notes**: Use liquid formulation or compounded suspension. ### Infants (1-12 months) - **Dose**: **10-15 mg/kg/day** (for cholestatic conditions) - **Frequency**: Divided **2-3 times daily** - **Maximum**: **25 mg/kg/day** ### Children (1-12 years) **Cystic Fibrosis-Associated Liver Disease (CFLD)** - **Dose**: **10-15 mg/kg/day** - **Frequency**: Divided **2-3 times daily** - **Maximum**: Up to **25-30 mg/kg/day** for severe cases. ### Adolescents (13-18 years) - **Dose**: **Approach adult dosing** based on indication. - **Maximum**: **Adult dose** (e.g., **1500 mg/day** for PBC). ## Safety Information ### Contraindications - **Absolute**: Hypersensitivity to bile acids or UDCA. - **Absolute**: Acute cholecystitis, cholangitis, or biliary obstruction. - **Absolute**: Calcified cholesterol stones, radio-opaque stones, non-functioning gallbladder. - **Absolute**: Frequent episodes of biliary colic. ### Common Adverse Effects - **Very Common (>10%)**: None widely reported. - **Common (1-10%)**: Diarrhea, nausea, vomiting, dyspepsia, pruritus, rash. - **Serious but Rare**: Paradoxical worsening of liver enzymes (transient), exacerbation of psoriasis. ### Key Drug Interactions - **Bile acid sequestrants (e.g., cholestyramine)**: Decrease UDCA absorption. Administer UDCA **2 hours before or 4 hours after**. - **Aluminum-based antacids**: Reduce UDCA absorption. Administer UDCA **2 hours before or 4 hours after**. - **Estrogens/Oral Contraceptives**: May increase cholesterol saturation of bile, reducing UDCA efficacy. - **Clofibrate**: May increase cholesterol secretion into bile, counteracting UDCA. - **Dapsone, nitrendipine, cyclosporine**: UDCA may reduce their absorption. Monitor drug levels. ## Monitoring & Follow-up - **Before Treatment**: Liver function tests (AST, ALT, ALP, GGT, bilirubin), serum albumin. Gallstone patients: Abdominal ultrasound. - **During Treatment**: Liver function tests every **1-3 months** for first 6 months, then every **6-12 months**. Gallstone patients: Gallbladder ultrasound every **6 months**. - **Clinical Signs**: Worsening pruritus, jaundice, new or worsening abdominal pain, persistent severe diarrhea. ## Clinical Pearls - 💡 **Tip 1**: Administer with food to reduce GI upset and optimize absorption. - 💡 **Tip 2**: Gallstone dissolution can take **6-24 months**. Recurrence is common if treatment stops. - 💡 **Tip 3**: For PBC, UDCA improves biochemical parameters but is not a cure. Lifelong therapy is common. - 💡 **Tip 4**: Liquid formulations or crushed tablets can be used for pediatric patients or those with dysphagia. > **⚠️ Important**: This information is for educational purposes only. Always consult current prescribing information, local guidelines, and clinical judgment before prescribing.