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MEDICINE MONOGRAPH CODE: [5.8] ID: TIP-MED-000076

Lactulose

Active Ingredient / Scientific Identity: Lactulose • Class: Synthetic Non-Absorbable Disaccharide (Galactose-Fructose); Osmotic Laxative & Hepatic Encephalopathy Ammonia Detoxifier

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THE INDIAN PHARMACIST — Educational Reference Sheet
Profile: Lactulose ([5.8] | ID: TIP-MED-000076) • Last Reviewed: 2026-11-10
Source URL: https://theindianpharmacist.com/medicine/5-8-lactulose/
Generic / Entity NameLactulose ([5.8])
Verified Indian Brands / RefGeneric Compendial Entry (No Commercial Brand Claimed)
Pharmacological ClassSynthetic Non-Absorbable Disaccharide (Galactose-Fructose); Osmotic Laxative & Hepatic Enc
Available Dosage FormsOral Solution / Syrup: 10 g / 15 mL (667 mg/mL) in 100 mL, 200 mL, 450 mL bottles
Regulatory ClassificationSchedule H Prescription Drug (To be sold by retail on the prescription of a Registere
Key Warning & Review DateRenal: Negligible systemic absorption; safe in CKD, though monitor electrolytes if diarrhoea develops. Hepatic: Cornerstone t
Reviewed: 2026-11-10
Safety Matrix:⚖️ Legal Status: Schedule H Prescription Drug (To be sold by retail o✔️ Standard Clinical Dispensing Precautions

1. Clinical & Scientific Overview

Lactulose (TIP-MED-000076, Reference Code [5.8]) is classified under Gastrointestinal & Hepatobiliary Medicines (Ch 05) as a Synthetic Non-Absorbable Disaccharide (Galactose-Fructose); Osmotic Laxative & Hepatic Encephalopathy Ammonia Detoxifier. Within the Indian regulatory and compendial framework, it is governed under Schedule H Prescription Drug (To be sold by retail on the prescription of a Registered Medical Practitioner only — Drugs Rules 1945).

Verified Indian Market Examples / Compendial Status:
Representative Indian Market Examples (Edition 2.7 Ch 05 [5.8], p. 63): Duphalac (Abbott), Looz (Intas), Evict (Albert David), Livoluk (Panacea), Cadilose (Zydus) — Strengths & Dosage Forms: Oral Solution / Syrup: 10 g / 15 mL (667 mg/mL) in 100 mL, 200 mL, 450 mL bottles
Representative Indian Market Examples (Edition 2.7 Ch 05 [5.8], p. 63): Duphalac (Abbott), Looz (Intas), Evict (Albert David), Livoluk (Panacea), Cadilose (Zydus) — Strengths & Dosage Forms: Oral Solution / Syrup: 10 g / 15 mL (667 mg/mL) in 100 mL, 200 mL, 450 mL bottles
Dosage Forms & Available Strengths:
Oral Solution / Syrup: 10 g / 15 mL (667 mg/mL) in 100 mL, 200 mL, 450 mL bottles
Routes: Oral / Parenteral / Topical as specified by formulation

3. Mechanism of Action & Pharmacodynamics

Synthetic Non-Absorbable Disaccharide (Galactose-Fructose); Osmotic Laxative & Hepatic Encephalopathy Ammonia Detoxifier acting on target receptor/enzyme pathways in Gastrointestinal & Hepatobiliary Medicines (Ch 05): clinical efficacy is mediated via Synthetic Non-Absorbable Disaccharide (Galactose-Fructose); Osmotic Laxative & Hepatic Encephalopathy Ammonia Detoxifier for Chronic constipation (especially in elderly, opioid-induced, post-surgical/haemorrhoidectomy, and pregnancy); prevention and treatment of portal-systemic hepatic encephalopathy in liver cirrhosis (colonic bacteria ferment lactulose to lactic/acetic acid, lowering colonic pH to ~5.0 and trapping diffusible NH3 as non-absorbable ammonium ion NH4+)..

4. Therapeutic Indications & Evidence-Supported Uses

  • Chronic constipation (especially in elderly, opioid-induced, post-surgical/haemorrhoidectomy, and pregnancy)
  • prevention and treatment of portal-systemic hepatic encephalopathy in liver cirrhosis (colonic bacteria ferment lactulose to lactic/acetic acid, lowering colonic pH to ~5
  • 0 and trapping diffusible NH3 as non-absorbable ammonium ion NH4+)

🇮🇳 Jurisdiction & Indication Note: Indications and schedules reflect Indian compendial and regulatory records (CDSCO / Indian Pharmacopoeia & NFI / NLEM 2022). Where international reference labels (US FDA DailyMed / NCBI StatPearls) are cited for pharmacokinetic or mechanistic parameters, international approvals do not automatically imply CDSCO approval in India.

5. Educational Dosage Context, Formulations & Administration

Educational Dosing & Regimen Summary: General Adult Reference: Constipation: Initially 15 mL to 30 mL (10–20 g) once daily at bedtime (or divided BD); adjust to 10–15 mL daily to produce 1 soft stool/day. Hepatic Encephalopathy: 30 mL to 45 mL three to four times daily, titrated specifically to produce 2 to 3 soft stools per day. Follow physician prescription.

Administration & Meal Timing: With or without food; may be mixed with water, milk, or fruit juice to mask the intensely sweet taste. | Constipation: Once daily at bedtime (onset of bowel movement takes 24 to 48 hours). Hepatic Encephalopathy: 3–4 times daily.

6. Pharmacokinetics, Metabolism & Renal/Hepatic Adjustment

Absorption & Disposition:
Absorption, distribution, metabolism, and excretion follow class pharmacokinetic profile; verify patient renal/hepatic function.
Metabolism & Biotransformation:
Renal: Negligible systemic absorption; safe in CKD, though monitor electrolytes if diarrhoea develops. Hepatic: Cornerstone therapy in decompensated hepatic cirrhosis!
Elimination & Renal Adjustment:
Renal: Negligible systemic absorption; safe in CKD, though monitor electrolytes if diarrhoea develops. Hepatic: Cornerstone therapy in decompensated hepatic cirrhosis!
Hepatic Impairment Considerations:
Renal: Negligible systemic absorption; safe in CKD, though monitor electrolytes if diarrhoea develops. Hepatic: Cornerstone therapy in decompensated hepatic cirrhosis!

7. Contraindications, Precautions & High-Risk Warnings

Contraindications & Red-Flag Precautions:
  • Contraindicated in galactosaemia, complete gastrointestinal obstruction, or digestive perforation. Caution in patients with lactose intolerance (syrup contains small residual amounts of free galactose and lactose).

Key Clinical Precautions: Renal: Negligible systemic absorption; safe in CKD, though monitor electrolytes if diarrhoea develops. Hepatic: Cornerstone therapy in decompensated hepatic cirrhosis!

8. Adverse Effects Profile

Common & Mechanism-Related Adverse Effects:
  • Abdominal flatulence, bloating, intestinal cramping, and belching during the first few days (due to bacterial gas production—usually subsides), dose-dependent osmotic diarrhoea.
  • Hypernatraemia, hypokalaemia, and severe dehydration if excessive high-dose diarrhoea occurs (especially in elderly encephalopathic patients who cannot drink water freely).
Serious / Dose-Limiting Adverse Effects:
  • Monitor for severe hypersensitivity, organ toxicity, or dose-limiting adverse events.

9. Major Drug–Drug, Drug–Food & Drug–Herb Interactions

  • Broad-spectrum oral antibiotics (neomycin, metronidazole, ciprofloxacin) may alter colonic saccharolytic flora, theoretically reducing acidification (though rifaximin + lactulose is standard synergistic therapy in hepatic encephalopathy)
  • Oral antacids inhibit the drop in colonic pH
  • Diuretic-induced hypokalaemia is worsened by lactulose-induced diarrhoea (increasing digoxin toxicity)

10. Clinical Monitoring, Patient Counselling & Storage

Clinical & Laboratory Monitoring: Monitor clinical response, baseline renal/hepatic parameters, and relevant serum biomarkers.

Pharmacist Patient Counselling Points:

  • Patient Counselling Checklist: Inform patients using lactulose for constipation that it is a gentle stool softener that takes 1 to 2 days (24–48 hours) to start working—it is not an overnight stimulant purge. Drink a full glass of water after taking the measured dose cup. In cirrhosis caregivers, explain that passing 2–3 soft stools daily is the exact goal that keeps toxic ammonia out of the brain.
  • Meal & Clock Timing Instruction: With or without food; may be mixed with water, milk, or fruit juice to mask the intensely sweet taste. (Constipation: Once daily at bedtime (onset of bowel movement takes 24 to 48 hours). Hepatic Encephalopathy: 3–4 times daily.)
  • Missed Dose Protocol: Take as soon as remembered; skip if close to next dose. Never double.
  • Geriatric Dispensing Pearl: Safe long-term laxative in elderly patients; monitor closely for dehydration and hypernatraemia if watery diarrhoea(>3 stools/day) develops.

Storage, Stability & Dispensing Safeguards: Store below 25°C–30°C in original moisture- and light-resistant packaging out of reach of children. Available forms: Oral Solution / Syrup: 10 g / 15 mL (667 mg/mL) in 100 mL, 200 mL, 450 mL bottles

11. Visual Pharmacology & Mechanism Diagram (svg-v339-01-adme-12-step-journey)

THE 12-STEP ORAL DRUG JOURNEY THROUGH THE HUMAN BODY (LADME) Note: IV bolus enters Step 6 directly (F = 100%); Sublingual & Transdermal routes bypass Step 4–5 Portal First-Pass Metabolism 1. Oral Administration • Tablet / Capsule swallowed • Gastric emptying to duodenum pH 1.5–3.5 (Stomach) 2. Disintegration & Dissolution • Tablet breaks into granules • API dissolves in GI fluid Noyes-Whitney Dissolution Rate 3. GI Epithelial Absorption • Crosses intestinal villi • Passive / Active / P-gp efflux Small Intestine (Large Surface Area) 4. Portal Circulation • Mesenteric veins → Portal vein • Delivers blood to liver sinusoids Pre-systemic Venous Conduit 5. First-Pass Metabolism • Gut & hepatic CYP450 extraction • High: GTN, Propranolol, Morphine Determines Bioavailability (F = f_a × (1-E_H)) 6. Systemic Circulation • Hepatic vein → IVC → Heart • Unbound vs Albumin-bound drug Only FREE drug is active 7–8. Tissue Distribution (Vd) • Capillary permeation to organs • Blood-Brain & Placental barriers Vd = Dose / C_0 (L or L/kg) 9. Target Site of Action • Receptors (GPCR, Ion channel) • Enzymes & Carrier Transporters Pharmacodynamic Effect (E_max, EC50) 10. Hepatic Biotransformation • Phase I (CYP450 Oxidation/Hydrolysis) • Phase II (Glucuronidation/Sulfation) Converts lipophilic drug → hydrophilic metabolite 11. Renal & Biliary Elimination • Nephron: Filtration + Secretion − Reabsorption • Biliary excretion & Enterohepatic recycling Total Clearance CL_tot = CL_renal + CL_hepatic 12. Excretion from the Body • Urine (Primary polar metabolite route) • Bile/Faeces, Expired Air, Sweat, Milk Elimination Half-Life t1/2 = (0.693 × Vd) / CL
svg-v339-01-adme-12-step-journey — 8.1 Complete 12-Step Journey of an Orally Administered Drug (ADME): Figure 8.1: The 12-step physiological journey of a typical orally administered solid dosage form through Liberation, Absorption, Distribution, Metabolism, and Excretion (LADME). Note: Parenteral (IV), sublingual, and inhalational routes bypass gastrointestinal absorption and/or hepatic first-pass metabolism.

12. Authoritative References, Regulatory Sources & Editorial Disclaimer

Primary Compendial & Guideline Reference: Indian Pharmacist Desk Reference — Professional Edition 2.7 (2026–27) • Ch 05 [5.8] (p. 63)

Official Verification Portals: Indian Pharmacopoeia Commission (IPC) & National Formulary of India (NFI) • Central Drugs Standard Control Organization (CDSCO) • Ministry of Health & Family Welfare — NLEM 2022 • NCBI Bookshelf / StatPearls Pharmacology Reference • DailyMed (US FDA Official Prescribing Reference)

Last Medically & Pharmaceutically Reviewed: 2026-11-10 • Verification Status: HANDBOOK_SOURCE_CONTENT

Educational & Clinical Disclaimer: This reference profile is published solely for pharmacy education, academic study, and professional clinical reference. It does not substitute for patient-specific clinical judgement, qualified specialist oncology/medical supervision, or official CDSCO/IP prescribing information. Never self-medicate with prescription, Schedule H/H1/X, NDPS, or oncology medicines.

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Educational Reference Notice: This printout from THE INDIAN PHARMACIST (https://theindianpharmacist.com/medicine/5-8-lactulose/, Last Reviewed: 2026-11-10) is an educational reference sheet for students and healthcare learners. It is NOT an official prescribing guideline or patient-specific treatment order.