Lactulose Dosage

Medically reviewed by Drugs.com. Last updated on Sep 27, 2024.

Usual Adult Dose for Constipation - Chronic

15 mL orally once a day.

Usual Adult Dose for Constipation - Acute

Initial dose: 15 mL orally once a day. Therapy should be continued until normal bowel function resumes.

Usual Adult Dose for Hepatic Encephalopathy

Initial dose: 30 mL orally 3 times a day or
300 mL in 700 mL water or normal saline as an enema retained for 30 to 60 minutes every 4 to 6 hours.
Maintenance dose: 30 to 45 mL orally 3 times a day.

Usual Pediatric Dose for Hepatic Encephalopathy

Infants: 1.7 to 6.7 g/day (2.5 to 10 mL) orally daily divided in 3 to 4 doses. Adjust dosage to produce 2 to 3 soft stools per day.

Children: 26.7 to 60 g/day (40 to 90 mL) orally daily divided in 3 to 4 doses. Adjust dosage to produce 2 to 3 soft stools per day.

Usual Pediatric Dose for Constipation - Chronic

Children: 0.7 to 2 g/kg/day (1 to 3 mL/kg/day) orally in divided doses daily; generally recommended not to exceed the adult maximum of 40 g/day (60 mL/day).

Renal Dose Adjustments

Data not available

Liver Dose Adjustments

Data not available

Dose Adjustments

Some patients require a higher initial dose (30 to 45 mL per day) for constipation. Once symptoms resolve, a lower maintenance dose should be used.

Dosage should be adjusted to produce 2 to 3 soft (but not diarrheal) stools per day.

If rapid laxation for hepatic encephalopathy is required, 30 to 45 mL may be given every hour until laxation is achieved.

Precautions

Lactulose solution contains galactose and lactose. It is contraindicated in patients on a low galactose diet, and should be used with caution in diabetics.

Elderly and debilitated patients receiving lactulose for more than six months should have serum electrolytes measured periodically.

Due to an accumulation of hydrogen gas in the intestines, the manufacturers of lactulose products suggest a theoretical possibility of an explosion in patients treated with lactulose who undergo electrocautery procedures. A thorough bowel cleansing with a non-fermentable solution is recommended in such patients.

Dialysis

Data not available. However, since lactulose is similar to sucrose in its molecular structure, it is likely to be dialyzable.

Other Comments

It may take 24 to 48 hours before a response is noted. The maximum recommended dose is 60 mL.

Frequently asked questions

• Which drugs cause opioid-induced constipation?

Further information

Always consult your healthcare provider to ensure the information displayed on this page applies to your personal circumstances.

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