What is the appropriate daily dose of Ursodeoxycholic acid (Ursofalk) for a 46‑kg patient when only 250‑mg tablets are available?

Ursodeoxycholic Acid (Ursofalk) Dosing for 46 kg Patient

For a 46 kg patient, the appropriate daily dose of ursodeoxycholic acid is 460-690 mg/day (10-15 mg/kg/day), which translates to 2 tablets of 250 mg twice daily (total 500 mg/day) as the practical dosing regimen using available 250 mg tablets. 1, 2

Dose Calculation Based on Indication

The specific indication determines the exact dosing:

For Intrahepatic Cholestasis of Pregnancy (Most Common Indication)

• Standard dose: 10-15 mg/kg/day divided into 2-3 doses 1, 2
• For 46 kg patient: 460-690 mg/day
• Practical regimen: 250 mg twice daily (500 mg/day total) 1
• This can be titrated up to 250 mg three times daily (750 mg/day) if pruritus persists, with maximum dose of 21 mg/kg/day (966 mg/day for 46 kg) 2
• Pruritus typically improves within 1-2 weeks, biochemical markers within 3-4 weeks 2

For Primary Biliary Cholangitis (If Applicable)

• Standard dose: 13-15 mg/kg/day, typically as single bedtime dose 2, 3, 4
• For 46 kg patient: 598-690 mg/day
• Practical regimen: 250 mg three times daily (750 mg/day total) or 500 mg at bedtime 2, 5
• The bedtime dosing strategy reduces the minimum effective dose and improves bile acid enrichment 5

For Primary Sclerosing Cholangitis (If Applicable)

• If used at all: 15-20 mg/kg/day maximum 1, 2
• For 46 kg patient: 690-920 mg/day
• Practical regimen: 250 mg three times daily (750 mg/day) 1
• Critical warning: Never exceed 20 mg/kg/day (920 mg/day for 46 kg) in PSC, as doses of 28-30 mg/kg/day significantly worsen outcomes 2, 6

Practical Dosing Algorithm

Step 1: Determine the indication (cholestasis of pregnancy, PBC, PSC, or gallstone dissolution)

Step 2: Calculate weight-based dose:

• 46 kg × 10 mg/kg = 460 mg/day (minimum)
• 46 kg × 15 mg/kg = 690 mg/day (standard maximum)

Step 3: Round to practical tablet combinations using 250 mg tablets:

• 500 mg/day = 2 tablets (250 mg twice daily) - appropriate for most indications 1
• 750 mg/day = 3 tablets (250 mg three times daily) - for higher dosing needs 1, 2

Step 4: Adjust based on response:

• For cholestasis of pregnancy: Start with 500 mg/day, increase to 750 mg/day if pruritus persists after 1-2 weeks 2
• For PBC: Consider single bedtime dose of 500-750 mg for improved efficacy 5

Important Caveats

• Divided dosing (2-3 times daily) is preferred for cholestasis of pregnancy, while single bedtime dosing may be used for PBC 1, 2, 5
• Do not abruptly discontinue once started, as this causes worsening liver biochemistry and return of pruritus 2, 6
• Monitor liver function tests to assess treatment response 2
• Ursodeoxycholic acid is safe during pregnancy and breastfeeding 2
• If diarrhea develops, treat symptomatically rather than discontinuing; severe persistent diarrhea is rare at standard doses 6