Osmotic Laxative·Gastrointestinal - Laxatives

Lactulose

Hepatic encephalopathy, chronic constipation

PBSOSMOTICActilax, DuphalacExtremely sweet, viscous syr…UNSCHEDULED+1

No source link confirmed for this record yet. Its own source notes are under Additional.

At a glance

Max Dose

45 mL/day (Aperient)

Onset

1-2 Days

Caution: Flatulence

HIGH

Hepatic Enceph.

INDICATED

Cautions

Avoid / Cautions

Bowel obstruction, Galactosemia. Pregnancy Category A. Not systemically absorbed.

Where it stands

Rapid Summary

Overview

Synthetic, non-digestible sugar. Acts as a slow osmotic laxative. Crucially, it acts as a bacterial sink for ammonia in patients with liver failure.

Clinical Focus

Slow onset. Causes massive gas production and bloating. Often poorly tolerated for simple constipation compared to Movicol.

Bottom Line

Lactulose is a first-line osmotic laxative for constipation and hepatic encephalopathy, but causes significant bloating and flatulence and takes 24-48 hours to work.

Formulation & Access

Brand Names

Actilax, Duphalac

Oral Routes

Extremely sweet, viscous syrup (3.3 g/5 mL).

Prescribing & PBS

Over The Counter (OTC).

Indications & Use

Primary

PBSTGA

Hepatic encephalopathy, chronic constipation.

Clinical Place

The gold-standard baseline therapy for preventing and treating confusion in liver cirrhosis.

Quick reference

Class & Role

Osmotic Laxative — Synthetic, non-digestible sugar.

Route / Formulation

Extremely sweet, viscous syrup (3.3 g/5 mL). (Actilax, Duphalac)

Usual Dose & Max

PO 15 mL OD to BD. Max 45 mL/day.

Key Indication Doses

Constipation: adults usually 15-45 mL daily initially, then 15-30 mL daily maintenance. Hepatic encephalopathy: PO 30-45 mL TDS-QID, titrated to 2-3 soft stools/day.

Best Uses

Lactulose is a first-line osmotic laxative for constipation and hepatic encephalopathy, but causes significant bloating and flatulence and takes 24-48 hours to work.

Key Risks

Gastrointestinal: Severe flatulence, bloating, abdominal cramps, explosive diarrhea (if overdosed). Metabolic: Hypernatremia and dehydration (due to free water loss in stool if taken in massive doses for encephalopathy).

Key Interactions

Theoretically, oral antibiotics (like Neomycin) can kill the colonic bacteria needed to ferment lactulose, reducing its efficacy, but in practice, they are often used together successfully for encephalopathy.

Monitoring

Strict stool charting. Target for hepatic encephalopathy is exactly 2-3 soft stools per day. If they have 0, they will get confused. If they have 10, they will dehydrate. Monitor U&E (sodium) during aggressive therapy.

Clinical Pearl

Even though it is a sickly sweet sugar syrup, Lactulose is NOT digested or absorbed by humans. It is entirely safe to give to severe diabetics and will not spike their BSL.

Access

Actilax, DuphalacExtremely sweet, viscous syr…

Brand: Actilax, Duphalac
Formulation: Extremely sweet, viscous syrup (3.3 g/5 mL).

From this page

No calculator, monitoring schedule or factsheet is linked to this medicine page yet.

Osmotic Laxative·Gastrointestinal - Laxatives

Lactulose

Hepatic encephalopathy, chronic constipation

PBSOSMOTICActilax, DuphalacExtremely sweet, viscous syr…UNSCHEDULED+1

No source link confirmed for this record yet. Its own source notes are under Additional.

At a glance

Max Dose

45 mL/day (Aperient)

Onset

1-2 Days

Caution: Flatulence

HIGH

Hepatic Enceph.

INDICATED

Cautions

Avoid / Cautions

Bowel obstruction, Galactosemia. Pregnancy Category A. Not systemically absorbed.

Where it stands

Rapid Summary

Overview

Synthetic, non-digestible sugar. Acts as a slow osmotic laxative. Crucially, it acts as a bacterial sink for ammonia in patients with liver failure.

Clinical Focus

Slow onset. Causes massive gas production and bloating. Often poorly tolerated for simple constipation compared to Movicol.

Bottom Line

Lactulose is a first-line osmotic laxative for constipation and hepatic encephalopathy, but causes significant bloating and flatulence and takes 24-48 hours to work.

Formulation & Access

Brand Names

Actilax, Duphalac

Oral Routes

Extremely sweet, viscous syrup (3.3 g/5 mL).

Prescribing & PBS

Over The Counter (OTC).

Indications & Use

Primary

PBSTGA

Hepatic encephalopathy, chronic constipation.

Clinical Place

The gold-standard baseline therapy for preventing and treating confusion in liver cirrhosis.

Quick reference

Class & Role

Osmotic Laxative — Synthetic, non-digestible sugar.

Route / Formulation

Extremely sweet, viscous syrup (3.3 g/5 mL). (Actilax, Duphalac)

Usual Dose & Max

PO 15 mL OD to BD. Max 45 mL/day.

Key Indication Doses

Constipation: adults usually 15-45 mL daily initially, then 15-30 mL daily maintenance. Hepatic encephalopathy: PO 30-45 mL TDS-QID, titrated to 2-3 soft stools/day.

Best Uses

Lactulose is a first-line osmotic laxative for constipation and hepatic encephalopathy, but causes significant bloating and flatulence and takes 24-48 hours to work.

Key Risks

Key Interactions

Monitoring

Clinical Pearl

Even though it is a sickly sweet sugar syrup, Lactulose is NOT digested or absorbed by humans. It is entirely safe to give to severe diabetics and will not spike their BSL.

Access

Actilax, DuphalacExtremely sweet, viscous syr…

Brand: Actilax, Duphalac
Formulation: Extremely sweet, viscous syrup (3.3 g/5 mL).

From this page

No calculator, monitoring schedule or factsheet is linked to this medicine page yet.