What is the medication Ursa used for?

October 8, 2025 •

4 min read

Gallstone disease is a common and costly digestive disorder in the United States. This article explores a key treatment: what is the medication Ursa used for? Ursa, also known as ursodiol, is a bile acid used to manage specific liver and gallbladder conditions.

Quick Summary

This content details the uses of the medication Ursa (ursodiol), a bile acid agent. It covers its primary functions in dissolving cholesterol gallstones and treating primary biliary cholangitis (PBC), an autoimmune liver disease.

Key Points

Primary Uses: Ursa (ursodiol) is mainly used to dissolve small, non-calcified cholesterol gallstones and to treat the autoimmune liver disease Primary Biliary Cholangitis (PBC).
Mechanism: It works by decreasing cholesterol production in the liver and dissolving cholesterol in bile, making stones less likely to form and helping to break down existing ones.
PBC Treatment: For PBC, ursodiol is a first-line therapy that slows liver damage progression and can delay the need for a liver transplant.
Gallstone Prevention: It is also effective in preventing gallstone formation in obese patients who are undergoing rapid weight loss.
Administration: Dosage is determined by a healthcare provider and the medication is typically taken in divided doses with food; treatment can last for months or years.
Side Effects & Interactions: Common side effects are generally mild (e.g., headache, diarrhea), but it can interact with antacids and cholesterol medications.
Effectiveness: While effective, gallstone dissolution is not always complete, and stones can recur in up to 50% of patients within five years.

Understanding Ursa (Ursodiol)

The medication known by brand names such as Urso 250, Urso Forte, and Actigall contains the active ingredient ursodiol, also called ursodeoxycholic acid (UDCA). It is a naturally occurring bile acid found in small amounts in human bile. Classified as a gallstone dissolution agent, its primary therapeutic actions involve altering the composition of bile to treat and prevent specific hepatobiliary conditions.

Ursodiol is available by prescription only, in both capsule and tablet forms. The tablet formulation is typically used for treating primary biliary cholangitis, while capsules are used for managing gallstones.

How Does Ursa Work? The Mechanism of Action

Ursodiol's effectiveness stems from its multi-faceted mechanism of action that benefits the liver and gallbladder. Its primary functions include:

Reducing Cholesterol Saturation: Ursa decreases the liver's synthesis and secretion of cholesterol and also inhibits the intestines from absorbing it. This process lowers the overall cholesterol concentration in the bile. Bile that is less saturated with cholesterol is less likely to form stones and can help dissolve existing ones.
Altering the Bile Acid Pool: The medication shifts the balance of bile acids from more toxic, water-repelling (hydrophobic) acids to more beneficial, water-attracting (hydrophilic) ones like UDCA itself. This change helps protect liver cells (hepatocytes) from the damaging effects of toxic bile acid buildup, which is a key problem in cholestatic liver diseases.
Cytoprotective and Immunomodulatory Effects: Ursodiol protects liver cells from injury by preserving their structure, including plasma membranes and mitochondria, and by stimulating anti-apoptotic (cell-survival) pathways. It also appears to have an immunomodulating effect, such as reducing the expression of certain antigens on liver cells that could otherwise trigger immune-mediated damage.
Stimulating Bile Flow (Choleretic Effect): Ursa helps to increase the secretion and flow of bile. This choleretic effect is crucial for flushing out toxic bile acids and reducing cholestasis (the slowing or stoppage of bile flow).

Primary FDA-Approved Uses for Ursa

The U.S. Food and Drug Administration (FDA) has approved ursodiol for two main conditions:

Dissolving Gallstones

Ursa is indicated for patients with radiolucent (not visible on a standard X-ray), non-calcified cholesterol gallstones that are smaller than 20 mm in diameter. It serves as a non-surgical option for patients who are not good candidates for gallbladder removal surgery (cholecystectomy) due to increased surgical risk or for those who refuse surgery. It is important to note that treatment can take several months to two years, and gallstones may recur in up to 50% of patients within five years after successful dissolution.

Treating Primary Biliary Cholangitis (PBC)

Ursa is a first-line therapy for Primary Biliary Cholangitis (PBC), an autoimmune disease where the body's immune system progressively destroys the small bile ducts in the liver. While it does not cure PBC, ursodiol slows the progression of liver damage, improves liver function tests, and can significantly delay the need for a liver transplant, particularly when started in the early stages of the disease.

Common Off-Label and Other Uses

Beyond its primary indications, clinicians use Ursa for several other conditions:

Prevention of Gallstones During Rapid Weight Loss: Obese patients undergoing very-low-calorie diets or bariatric surgery are at high risk of forming gallstones. Ursodiol is effectively used to prevent their formation in this population.
Intrahepatic Cholestasis of Pregnancy (ICP): This is a liver condition that occurs in late pregnancy, causing intense itching and elevated bile acids. Ursodiol is used off-label to relieve maternal symptoms and reduce bile acid levels.
Primary Sclerosing Cholangitis (PSC): While its use in PSC is more controversial and not FDA-approved, some experts recommend moderate doses of ursodiol as it may improve liver function tests.
Other Conditions: It's also used off-label for cystic fibrosis-related liver disease, liver problems after transplantation, and other cholestatic conditions.

Ursa vs. Other Treatments

Here is a comparison of Ursa (ursodiol) with another bile acid agent, chenodiol, and surgical intervention for gallstones.


Treatment/Feature	Ursa (Ursodiol)	Chenodiol	Cholecystectomy (Surgery)
Mechanism	Decreases cholesterol in bile, making it less likely to form stones.	Also decreases cholesterol saturation of bile.	Surgical removal of the gallbladder.
Efficacy	Effective for small (<20mm), non-calcified cholesterol stones.	Can dissolve stones, but is now largely replaced by ursodiol.	Definitive treatment for gallstones of any type.
Side Effects	Generally well-tolerated. Can cause headache, diarrhea, or constipation.	Higher incidence of side effects, including diarrhea and potential for mild liver injury.	Risks associated with surgery and anesthesia.
Recurrence	Gallstones can recur in up to 50% of patients within 5 years.	High rate of recurrence after stopping therapy.	Eliminates gallstones permanently by removing the gallbladder.

Administration and Side Effects

Dosage of ursodiol is determined by a healthcare provider based on the patient's body weight and the condition being treated. It is crucial to take this medication exactly as prescribed. Treatment often requires regular monitoring, including blood tests for liver function and ultrasounds to check on gallstones.

Potential Side Effects

Common side effects are generally mild and may include headache, dizziness, back pain, diarrhea, constipation, nausea, and signs of a cold. Hair loss or thinning can also occur. More serious side effects requiring immediate medical attention include signs of an allergic reaction (hives, difficulty breathing), or new or worsening liver problems (jaundice, dark urine, severe stomach pain).

Drug Interactions

Certain medications can interfere with the absorption and effectiveness of ursodiol. These include aluminum-containing antacids, bile acid sequestrants like cholestyramine, and some cholesterol-lowering drugs. It's essential to inform a doctor of all medications being taken.

Conclusion

Ursa, or ursodiol, is a vital medication in the field of gastroenterology and hepatology. Its primary roles are as a non-surgical option for dissolving specific types of gallstones and as the cornerstone of therapy for primary biliary cholangitis, where it can significantly alter the disease's course and improve long-term outcomes. With a well-understood mechanism of action and a favorable safety profile, it remains an important tool for managing these complex liver and gallbladder conditions.

For more information on the uses and risks of ursodiol, visit the MedlinePlus drug information page.

Frequently Asked Questions

Ursa, with the active ingredient ursodiol, is primarily used to dissolve certain types of cholesterol gallstones as a non-surgical option and to treat an autoimmune liver disease called primary biliary cholangitis (PBC).

Ursa works by reducing the amount of cholesterol produced by the liver and secreted into bile. This change in bile composition helps dissolve the cholesterol that forms gallstones.

No, Ursa (ursodiol) does not cure PBC, but it is a first-line treatment that can slow the progression of liver damage, improve liver function, and delay the need for a liver transplant.

Treatment for dissolving gallstones can take several months, potentially up to two years. Even after successful dissolution, gallstones can recur.

Common side effects of Ursa (ursodiol) include headache, dizziness, diarrhea, constipation, upset stomach, back pain, and cold-like symptoms. Hair loss has also been reported.

Yes, it is generally recommended to take Ursa tablets with food to improve their effectiveness and absorption. The capsules may be taken with or without food.

Yes, Ursa is used to prevent the formation of gallstones in overweight individuals who are losing weight very quickly, such as after bariatric surgery or on a very-low-calorie diet.