URSO 250
Clinical safety rating: caution
Comprehensive clinical and safety monograph for URSO 250 (URSO 250).
Ursodeoxycholic acid (UDCA) reduces endogenous bile acid synthesis and secretion by inhibiting cholesterol absorption and decreasing bile acid hydrophobicity. It also displaces toxic endogenous bile acids from the enterohepatic circulation and exerts cytoprotective, anti-apoptotic, and immunomodulatory effects on hepatocytes and cholangiocytes.
| Metabolism | Conjugation with glycine and taurine in the liver; undergoes enterohepatic circulation with eventual renal excretion as conjugates. Minor metabolism via dehydroxylation by gut bacteria to lithocholic acid. |
| Excretion | Primarily fecal excretion (biliary) as unchanged drug; minimal renal excretion (<1%). Enterohepatic circulation occurs, with small amounts eliminated in bile. |
| Half-life | Terminal elimination half-life is approximately 3.5 to 5.8 days in patients with cholestatic liver disease, reflecting extensive enterohepatic recycling; in healthy individuals, half-life may be shorter. |
| Protein binding | Approximately 70% bound to plasma proteins, primarily albumin. |
| Volume of Distribution | 0.1-0.3 L/kg; small volume indicating limited extravascular distribution, consistent with predominant confinement to the enterohepatic circulation and bile. |
| Bioavailability | Oral bioavailability is low, approximately 20-30% due to extensive first-pass hepatic extraction; however, absorption is enhanced in the presence of bile acids. |
| Onset of Action | Oral: Onset of action is gradual; clinical effects on biliary cholesterol saturation may be observed within 1 to 4 weeks, but maximal therapeutic benefit in primary biliary cholangitis may require 1 to 3 months. |
| Duration of Action | Duration of action is prolonged due to enterohepatic circulation, with effects persisting for days after discontinuation; clinical improvement in liver biochemistries may take months. |
| Molecular Weight | 392.57 |
13-15 mg/kg/day orally in 2-4 divided doses for primary biliary cholangitis; 300 mg twice daily for gallstone dissolution.
| Dosage form | TABLET |
| Renal impairment | No specific dose adjustment required for renal impairment; use with caution in severe impairment (eGFR <30 mL/min) due to limited data. |
| Liver impairment | Child-Pugh A/B: No adjustment. Child-Pugh C: Avoid use or reduce dose to 10 mg/kg/day based on tolerability. |
| Pediatric use | 5-10 mg/kg/day orally in 2-3 divided doses for cholestatic liver disease; not established for gallstones. |
| Geriatric use | Initiate at lower end of dosing range (10-13 mg/kg/day) due to age-related reduced hepatic function; monitor liver function. |
| 1st trimester | Use only if clearly needed. No adequate studies in pregnant women. |
| 2nd trimester | Consider risks vs benefits. May be used for cholestasis of pregnancy. |
| 3rd trimester | Consider risks vs benefits. May be used for cholestasis of pregnancy. |
Clinical note
Comprehensive clinical and safety monograph for URSO 250 (URSO 250).
| Placental transfer | Ursodeoxycholic acid crosses the placenta; cord blood levels are approximately 20% of maternal serum levels. |
| Breastfeeding | Ursodeoxycholic acid is excreted into breast milk in small amounts; however, doses up to 1 g/day are considered compatible with breastfeeding. Monitor infant for diarrhea. |
| Lactation Rating |
■ FDA Black Box Warning
None
| Serious Effects |
Hypersensitivity to ursodeoxycholic acid or any bile acidComplete biliary obstructionInflammatory bowel disease of the small intestine or colon (relative, but considered absolute in some references)Pancreatitis (severe)Liver cirrhosis (decompensated)
| Precautions | Monitor liver function tests (LFTs) and bilirubin levels; discontinue if LFTs worsen or signs of cholestasis develop. May unmask or exacerbate hepatic decompensation in patients with cirrhosis. Use with caution in patients with chronic liver disease, pregnancy (Category B), or known hypersensitivity to bile acids. |
| Food/Dietary | Take with food to improve absorption. Avoid high-cholesterol foods as they may counteract the bile acid-lowering effect. No specific dietary restrictions but maintain a balanced diet. |
Loading safety data…
| L2 (Safer) |
| Teratogenic Risk | Ursodeoxycholic acid (UDCA) is not known to be teratogenic. Data from prospective studies in women with intrahepatic cholestasis of pregnancy (ICP) show no increased risk of congenital malformations. First trimester exposure: no evidence of teratogenicity. Second and third trimester exposure: used therapeutically for ICP, no fetal harm reported. |
| Fetal Monitoring | Monitor liver function tests (ALT, AST, GGT, bilirubin) and bile acids. In pregnancy, monitor fetal well-being with non-stress tests and biophysical profiles due to underlying ICP. |
| Fertility Effects | No known adverse effects on fertility. UDCA is used to improve bile flow and may benefit patients with primary biliary cholangitis, potentially improving fertility outcomes by reducing cholestasis-related hormonal disturbances. |
| Clinical Pearls | URSODIOL (URSO 250) is a hydrophilic bile acid that reduces cholesterol saturation in bile and promotes dissolution of cholesterol gallstones. It is also used in primary biliary cholangitis (PBC) to improve liver biochemistry. Monitor liver function tests (LFTs) and bilirubin at baseline and periodically. Efficacy in gallstone dissolution is higher for floating (radiolucent) stones <20 mm in diameter. Dose adjustment needed in cholestatic liver disease. May worsen pruritus initially in PBC. |
| Patient Advice | Take URSO 250 with food to enhance absorption and reduce gastrointestinal side effects. · Do not take with antacids containing aluminum (e.g., Maalox, Mylanta) as they bind and reduce efficacy. · For gallstones, treatment may take 6-24 months; ultrasound monitoring is required. · For PBC, medication is lifelong; do not discontinue without consulting your doctor. · Report worsening right upper quadrant pain, jaundice, or severe itching to your healthcare provider. |