Ursodeoxycholic Acid (UDCA) is a hydrophilic, tertiary bile acid used therapeutically as a hepatoprotective and choleretic agent. It is the standard first-line pharmacological therapy for primary biliary cholangitis (PBC) and is widely used for gallstone dissolution and various cholestatic liver conditions in India. It works by replacing toxic hydrophobic bile acids, stimulating bile flow, and exerting anti-apoptotic, anti-inflammatory, and immunomodulatory effects on hepatocytes and cholangiocytes.
Adult: PBC: 13-15 mg/kg/day in 2-4 divided doses with meals. For a 60kg adult, ~800-900 mg/day (e.g., 300mg three times daily). Gallstone Dissolution: 8-10 mg/kg/day in 2-3 divided doses, usually at bedtime. Common dose: 300mg twice daily.
Note: Take with or just after meals to enhance bile flow and improve tolerance. Tablets should be swallowed whole with a glass of water. For gallstone dissolution, the evening dose is particularly important. Therapy requires long-term commitment (months to years).
UDCA exerts multiple hepatoprotective mechanisms: 1) It replaces endogenous, cytotoxic hydrophobic bile acids (like chenodeoxycholic acid) in the bile acid pool, reducing their detergent-like damage to hepatocyte and cholangiocyte membranes. 2) It stimulates hepatobiliary secretion, inducing a bicarbonate-rich choleresis ('hypercholeresis'), which helps flush out toxic substances and prevents bile stasis. 3) In cholestasis, it activates alternative excretory pathways. 4) It stabilizes hepatocyte membranes against bile acid-induced apoptosis. 5) It has immunomodulatory effects, such as reducing the aberrant expression of MHC class I molecules on hepatocytes.
Pregnancy: Category B. Considered safe and is the drug of choice for Intrahepatic Cholestasis of Pregnancy (ICP). Benefits outweigh risks. Monitor LFTs.
Driving: No known effects on driving ability. Dizziness is a rare side effect.
| Cholestyramine, Colestipol, Colesevelam | Bile acid sequestrants bind UDCA in the intestine, drastically reducing its absorption and efficacy. | Major |
| Aluminum-based Antacids | May reduce absorption of UDCA. Administer at least 2 hours apart. | Moderate |
| Ciclosporin (Cyclosporine) | UDCA may increase the absorption of ciclosporin, potentially raising its blood levels and risk of toxicity. | Moderate |
| Oral Contraceptives, Estrogens | May counteract UDCA's effect by increasing cholesterol saturation of bile, reducing gallstone dissolution efficacy. | Moderate |
| Clofibrate, Fibrates | May increase cholesterol secretion into bile, antagonizing UDCA's effect on gallstones. | Moderate |
| Dapsone | UDCA may increase absorption of dapsone. | Minor |