Ursodiol

Dosage for Ursodiol is highly individualized and depends strictly on the condition being treated and the patient's body weight.

• Primary Biliary Cholangitis (PBC): The standard recommended dosage is 13 to 15 mg/kg/day. This total daily amount is usually divided into two to four doses and taken with food. For a person weighing 70 kg (154 lbs), this equates to approximately 900 mg to 1050 mg per day.
• Gallstone Dissolution: The typical dose is 8 to 10 mg/kg/day, usually divided into two or three doses. Treatment for gallstones is a long-term process; it may take 6 to 24 months to fully dissolve stones. If stones do not show signs of partial dissolution after 12 months, the success of continued therapy is unlikely.
• Prevention of Gallstones (Rapid Weight Loss): The standard dose is 300 mg taken twice daily (600 mg total per day) during the period of active weight loss.

Ursodiol is not FDA-approved for most pediatric conditions, but it is frequently used 'off-label' in children for conditions such as biliary atresia or cystic fibrosis-related liver disease. In these cases, pediatric specialists typically prescribe 15 to 30 mg/kg/day divided into two or three doses. Safety and effectiveness in children have not been established through large-scale clinical trials, so use in this population must be closely monitored by a pediatric hepatologist.

Renal Impairment

There are no specific dosage adjustment guidelines provided by the manufacturer for patients with kidney disease. However, because Ursodiol is primarily excreted through the feces and undergoes minimal renal clearance, it is generally considered safe for patients with renal impairment. Nonetheless, your doctor will monitor your overall health closely.

Hepatic Impairment

While Ursodiol is used to treat liver disease, it should be used with extreme caution in patients with 'decompensated' liver disease (advanced cirrhosis where the liver can no longer function). If a patient has severe hepatic impairment or complete biliary obstruction, Ursodiol may not be effective and could potentially worsen the condition.

Elderly Patients

Clinical studies did not include sufficient numbers of subjects aged 65 and over to determine whether they respond differently from younger subjects. In general, dose selection for an elderly patient should be cautious, usually starting at the low end of the dosing range, reflecting the greater frequency of decreased hepatic, renal, or cardiac function.

To ensure maximum effectiveness and minimize side effects, follow these guidelines:

• Consistency: Take Ursodiol at the same times every day to maintain steady levels in your bile.
• With Food: It is generally recommended to take the tablets or capsules with a meal or a snack. This can help improve absorption and reduce the risk of stomach upset.
• Swallow Whole: Do not crush or chew the tablets or capsules unless specifically instructed by your pharmacist. Some tablets (like URSO Forte) are scored and can be broken in half if necessary, but they should still be swallowed without chewing to avoid a bitter taste.
• Storage: Store the medication at room temperature (68°F to 77°F or 20°C to 25°C) in a dry place away from direct sunlight.

If you miss a dose, take it as soon as you remember. If it is almost time for your next scheduled dose, skip the missed dose and resume your regular schedule. Do not 'double up' or take two doses at once to make up for a missed one, as this increases the risk of gastrointestinal side effects.

Ursodiol overdose is rare because the body has a limited capacity to absorb the drug; excess amounts are usually excreted in the feces. However, an overdose may cause severe diarrhea.

• Symptoms: Severe abdominal cramping and frequent watery stools.
• Emergency Measures: If an overdose is suspected, contact your local poison control center or seek emergency medical attention immediately. Treatment is generally supportive, focusing on maintaining hydration and electrolyte balance.

> Important: Follow your healthcare provider's dosing instructions exactly. Do not adjust your dose or stop taking the medication without medical guidance, as this can lead to a recurrence of symptoms or disease progression.

Ursodiol is generally well-tolerated, but because it alters the composition of bile, gastrointestinal symptoms are the most frequently reported issues.

• Diarrhea: This is the most common side effect. It occurs because the increased concentration of bile acids in the intestine can pull water into the colon. It is usually mild and may resolve as your body adjusts to the medication.
• Constipation: Conversely, some patients experience a slowing of bowel movements.
• Dyspepsia (Indigestion): You may feel a sensation of fullness, bloating, or gas after eating.
• Nausea: Mild stomach queasiness, particularly when starting the medication.

• Headache and Dizziness: Some patients report mild neurological symptoms that usually dissipate over time.
• Abdominal Pain: Specifically in the upper right quadrant, where the liver and gallbladder are located.
• Back Pain: Muscle or joint aches have been noted in clinical trials for PBC.
• Pruritus (Itching): While Ursodiol is often used to treat itching caused by liver disease, in some cases, it can temporarily worsen the sensation when therapy first begins.

• Leukopenia: A rare decrease in the white blood cell count, which may increase the risk of infection.
• Skin Rash or Urticaria (Hives): This may indicate a mild allergic reaction to the drug or its inactive ingredients.
• Hair Thinning: A very small percentage of patients report temporary hair loss (alopecia). This is usually not permanent.

While rare, serious complications can occur. You should contact your healthcare provider immediately if you experience:

• Severe Allergic Reaction (Anaphylaxis): Symptoms include swelling of the face, lips, or tongue; difficulty breathing; or a widespread, blistering rash.
• Biliary Obstruction: If you develop sudden, intense pain in the upper right abdomen, yellowing of the skin or eyes (jaundice), or very dark urine, it may indicate that a gallstone has moved and blocked a bile duct.
• Worsening Liver Function: While Ursodiol is meant to help the liver, in rare cases of advanced disease, it may lead to increased liver enzymes. Your doctor will monitor these via regular blood tests.

> Warning: Stop taking Ursodiol and call your doctor immediately if you experience signs of a severe allergic reaction or sudden, debilitating abdominal pain.

Ursodiol is often taken for many years, or even for a lifetime in the case of PBC.

• Calcification of Gallstones: In some patients being treated for gallstone dissolution, the stones may become calcified (hardened with calcium) over time. Once stones are calcified, Ursodiol can no longer dissolve them, and surgery may become necessary.
• Weight Changes: While not directly linked to weight gain, changes in digestion and metabolism of fats may lead to slight weight fluctuations in some individuals.

No FDA black box warnings currently exist for Ursodiol. It is considered a safe medication when used as directed for its approved indications. However, it is critical to distinguish Ursodiol from other bile acids (like obeticholic acid) which do have black box warnings for liver failure risk in certain populations.

Report any unusual or persistent symptoms to your healthcare provider. Keeping a 'symptom diary' can be helpful when discussing side effects with your doctor during follow-up appointments.

Ursodiol is a specialized medication that requires ongoing medical supervision. It is not a 'quick fix' for gallbladder issues and requires months of consistent use. Patients must be aware that Ursodiol cannot dissolve all types of gallstones—only those primarily made of cholesterol. If your gallstones are made of bile pigments or have high calcium content (radio-opaque), Ursodiol will not be effective.

As of 2026, there are no FDA black box warnings for Ursodiol. It has a long-standing safety profile since its initial approval in the 1980s.

• Hepatotoxicity (Liver Toxicity): Although Ursodiol is used to treat liver disease, patients with advanced cirrhosis must be monitored closely. There is a theoretical risk that the metabolite lithocholic acid could cause further liver damage in individuals who cannot properly detoxify it.
• Biliary Obstruction: Ursodiol should not be used if there is a complete blockage of the bile ducts. Increasing bile flow against a complete obstruction can lead to serious complications, including gallbladder rupture or severe infection (cholangitis).
• Gallbladder Non-Visualization: If a gallbladder cannot be seen on an oral cholecystogram (a specific type of X-ray), it usually means the gallbladder is not functioning or the duct is blocked. Ursodiol is generally not recommended in these cases.

Regular laboratory testing is a mandatory part of Ursodiol therapy. Your healthcare provider will likely order the following tests:

• Liver Function Tests (LFTs): These include AST, ALT, and Alkaline Phosphatase (ALP). During the first three months of treatment, these are often checked every month. If levels do not improve or if they significantly increase, your doctor may discontinue the medication.
• Bilirubin Levels: To monitor for signs of jaundice or worsening cholestasis.
• Ultrasound or X-rays: For patients taking Ursodiol for gallstones, imaging is usually performed every 6 months to monitor the size and number of stones.

Ursodiol generally does not cause drowsiness or cognitive impairment. Most patients can safely drive or operate machinery while taking this medication. However, if you experience dizziness as a side effect, you should wait until you know how the medication affects you before engaging in these activities.

There is no direct chemical interaction between Ursodiol and alcohol. However, alcohol is a known liver toxin. Since Ursodiol is primarily prescribed for liver or gallbladder conditions, consuming alcohol can counteract the benefits of the medication and place additional stress on the liver. It is highly recommended to limit or avoid alcohol consumption while being treated for liver disease.

Ursodiol does not typically cause withdrawal symptoms, and tapering is not usually required. However, if you stop taking it for PBC, your liver enzymes will likely return to their abnormal pre-treatment levels, and the disease may begin to progress again. For gallstones, stopping treatment before the stones are fully dissolved will result in the stones remaining or even growing larger.

> Important: Discuss all your medical conditions, especially any history of liver failure or biliary blockages, with your healthcare provider before starting Ursodiol.

There are no medications that are strictly 'contraindicated' in a way that causes immediate life-threatening toxicity, but several drugs can make Ursodiol completely ineffective.

• Bile Acid Sequestrants (e.g., Cholestyramine, Colestipol, Colesevelam): These drugs are designed to bind bile acids in the gut to lower cholesterol. Unfortunately, they cannot distinguish between 'bad' bile acids and Ursodiol. If taken together, the sequestrant will bind the Ursodiol and prevent it from being absorbed.
• Management: Ursodiol must be taken at least 2 hours before or 4 to 6 hours after taking a bile acid sequestrant.

• Aluminum-Based Antacids: Many over-the-counter antacids (like Maalox or Mylanta) contain aluminum hydroxide. Aluminum can bind to Ursodiol in the stomach, significantly reducing its absorption.
• Management: Avoid taking aluminum-based antacids at the same time as Ursodiol. Switch to magnesium-based or calcium-based antacids if your doctor approves.

• Estrogens and Oral Contraceptives: Estrogens increase the secretion of cholesterol into the bile. This directly counteracts the primary goal of Ursodiol (which is to lower bile cholesterol). Taking birth control pills or hormone replacement therapy may make Ursodiol less effective at dissolving or preventing gallstones.
• Fibrates (e.g., Clofibrate, Fenofibrate): These cholesterol-lowering medications also increase the amount of cholesterol the liver puts into the bile, potentially promoting the formation of gallstones and neutralizing the effects of Ursodiol.
• Cyclosporine: Ursodiol may increase the absorption of cyclosporine (an immunosuppressant) in some patients. This could lead to toxic levels of cyclosporine in the blood.
• Management: Your doctor may need to monitor your cyclosporine blood levels more frequently and adjust the dose accordingly.

• High-Fat Meals: While Ursodiol should be taken with food, extremely high-fat meals can trigger gallbladder contractions. If you have active gallstones, this could potentially cause a 'gallbladder attack' (biliary colic). A balanced, low-cholesterol diet is generally recommended.
• Fiber: Very high-fiber diets can theoretically bind some bile acids, but this is usually not clinically significant for most patients.

• Milk Thistle (Silybum marianum): Often taken for liver health, milk thistle may have additive effects with Ursodiol. While not dangerous, you should inform your doctor if you are using it.
• Vitamin Supplements: Ursodiol can slightly improve the absorption of fat-soluble vitamins (A, D, E, and K) in patients who have cholestasis, which is generally a beneficial interaction.

Ursodiol does not typically interfere with common laboratory tests, but it is intended to change your Liver Function Test (LFT) results. It is important that your doctor knows you are taking Ursodiol when they interpret your AST, ALT, and ALP levels, as the medication should ideally be lowering these numbers.

> Important: Tell your doctor about ALL medications, supplements, and herbal products you are taking. Even 'natural' supplements can interfere with how your liver processes Ursodiol.

In certain clinical scenarios, the use of Ursodiol is strictly prohibited because the risks far outweigh any potential benefits:

1. 1Complete Biliary Obstruction: If the bile ducts are entirely blocked (by a tumor, stricture, or impacted stone), Ursodiol cannot flow into the intestine. Attempting to stimulate bile flow against a 'closed' system can cause a dangerous buildup of pressure in the liver and gallbladder, potentially leading to rupture or systemic infection.
2. 2Acute Cholecystitis: Patients with active inflammation or infection of the gallbladder should not start Ursodiol. This is a medical emergency that usually requires surgery or antibiotics.
3. 3Cholangitis: Infection of the bile duct system is a contraindication for starting bile acid therapy until the infection is resolved.
4. 4Biliary-Gastrointestinal Fistula: If there is an abnormal connection between the bile ducts and the intestines, the pharmacological action of Ursodiol may be unpredictable and dangerous.
5. 5Calcified Gallstones: Ursodiol only works on cholesterol stones. If an X-ray shows that gallstones are 'radio-opaque' (visible due to calcium content), Ursodiol is contraindicated because it will be ineffective, wasting valuable treatment time.

These are conditions where Ursodiol may be used, but only with extreme caution and frequent monitoring:

• Decompensated Cirrhosis: In patients with advanced liver failure (e.g., Child-Pugh Class C), the liver may not be able to conjugate Ursodiol properly, leading to a buildup of the drug and potential toxicity.
• Frequent Biliary Colic: If a patient is having frequent, severe gallbladder attacks, waiting months for Ursodiol to work may be inappropriate, and surgery should be considered instead.

Patients who have a known hypersensitivity or allergy to any bile acids (such as chenodiol or obeticholic acid) should not take Ursodiol, as there is a high risk of cross-reactivity. Symptoms of an allergic reaction include skin rash, itching, swelling, or difficulty breathing.

> Important: Your healthcare provider will evaluate your complete medical history, including recent imaging of your gallbladder and bile ducts, before prescribing Ursodiol.

Ursodiol is classified as Pregnancy Category B. This means that animal reproduction studies have failed to demonstrate a risk to the fetus, and there are no adequate and well-controlled studies in pregnant women.

• Clinical Use: Ursodiol is frequently used off-label to treat Intrahepatic Cholestasis of Pregnancy (ICP), a condition that causes severe itching and increases the risk of preterm birth. Many specialists consider it the treatment of choice for ICP, but it should only be used under the strict guidance of a high-risk obstetrician (Maternal-Fetal Medicine specialist).
• First Trimester: As with most medications, caution is advised during the first trimester when organogenesis (organ formation) occurs.

It is not known whether Ursodiol is excreted in human milk. However, because Ursodiol is a naturally occurring bile acid already present in the body, and because the amount absorbed by a nursing infant would likely be very small, many experts consider it 'likely compatible' with breastfeeding. Mothers should monitor their infants for any signs of diarrhea or upset stomach.

While not FDA-approved for children, Ursodiol is a mainstay in pediatric hepatology for conditions like Biliary Atresia (post-Kasai procedure) and Alagille Syndrome.

• Dosing: Pediatric doses are weight-based and often higher than adult doses (up to 30 mg/kg/day) because children clear the drug more quickly.
• Safety: Long-term safety data in children are limited, but the drug is generally considered safe when monitored by a specialist.

There is no evidence to suggest that patients over 65 require a different dose than younger adults. However, older adults are more likely to have other conditions (like heart or kidney disease) and take multiple medications.

• Polypharmacy: Careful attention must be paid to interactions with other drugs, especially bile acid sequestrants used for high cholesterol.
• Monitoring: Kidney and liver function should be assessed before starting therapy, as is standard for all new medications in the elderly.

No specific dose adjustments are required for patients with kidney disease. Ursodiol is primarily eliminated through the liver and feces. However, in patients with end-stage renal disease, the overall metabolic environment is altered, and these patients should be monitored for any unusual side effects.

• Mild to Moderate (Child-Pugh A/B): No dose adjustment is usually needed, but LFTs must be monitored monthly.
• Severe (Child-Pugh C): Use is generally avoided or used with extreme caution. If the liver cannot conjugate the drug, it will not be effective and could potentially accumulate to toxic levels.

> Important: Special populations require individualized medical assessment. Always inform your doctor if you are pregnant, planning to become pregnant, or nursing.

Ursodiol (Ursodeoxycholic acid) is a naturally occurring bile acid that constitutes about 1-3% of the total human bile acid pool. When administered therapeutically, it increases to 30-50% of the pool. Its primary molecular action is the solubilization of cholesterol. It does this by dispersing cholesterol into liquid crystals in the bile. Unlike its predecessor, chenodiol, Ursodiol does not inhibit the enzyme HMG-CoA reductase directly but rather reduces the rate at which the liver secretes cholesterol into the bile.

In chronic liver disease, Ursodiol acts as a choleretic (it increases bile flow). It protects the cholangiocytes (cells lining the bile ducts) from the detergent-like effects of hydrophobic bile acids like lithocholic acid and deoxycholic acid. It also stabilizes mitochondrial membranes and may inhibit apoptosis (cell death) pathways triggered by bile stasis.

The onset of action for improving liver enzymes in PBC is typically seen within 2 to 4 weeks, with maximal improvement occurring at 3 to 6 months. For gallstone dissolution, the process is much slower; the rate of dissolution is approximately 1 mm per month. Therefore, a 10 mm stone would take at least 10 months to dissolve. If the medication is stopped, the bile quickly reverts to its previous 'stone-forming' state, and stones may recur.

| Parameter | Value |

|---|---|

| Bioavailability | ~90% (Oral) |

| Protein Binding | 70% to 99% (Albumin/Lipoproteins) |

| Half-life | 3.5 to 5.8 days |

| Tmax | 1 to 3 hours |

| Metabolism | Hepatic conjugation (Glycine/Taurine) |

| Excretion | Fecal (>90%), Renal (<1%) |

• Molecular Formula: C24H40O4
• Molecular Weight: 392.57 g/mol
• Solubility: Practically insoluble in water; freely soluble in ethanol and glacial acetic acid.
• Structure: It is a 3α, 7β-dihydroxy-5β-cholan-24-oic acid. It is a stereoisomer of chenodiol, with the hydroxyl group at the 7-position in the 'beta' rather than 'alpha' orientation, which makes it significantly less toxic to cells.

Ursodiol is classified as a Bile Acid Therapy. Related medications include Chenodiol (rarely used now due to toxicity) and Obeticholic Acid (Ocaliva), which is a farnesoid X receptor (FXR) agonist used for PBC when Ursodiol is not enough. Ursodiol remains the foundational therapy for most cholestatic liver diseases.