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Accession NumberDB00581  (APRD01063)
TypeSmall Molecule

A synthetic disaccharide used in the treatment of constipation and hepatic encephalopathy. It has also been used in the diagnosis of gastrointestinal disorders. (From Martindale, The Extra Pharmacopoeia, 30th ed, p887)

4-O-beta-D-Galactopyranosyl-D-fructofuranoseNot AvailableNot Available
4-O-beta-D-Galactopyranosyl-D-fructoseNot AvailableNot Available
LactuloseNot AvailableINN, BAN, USAN, JAN
Prescription ProductsNot Available
Generic Prescription Products
NameDosageStrengthRouteLabellerMarketing StartMarketing End
Lactulosesolution10 g/15mLoralRoxane Laboratories, Inc1992-05-29Not AvailableUs 0a2ef1ad1c84951dc1392a8bbe1f3cb241c91ed59e44ad8268635315440d978c
Lactulosesolution10 g/15mLoralRoxane Laboratories, Inc1992-05-29Not AvailableUs 0a2ef1ad1c84951dc1392a8bbe1f3cb241c91ed59e44ad8268635315440d978c
Lactulosesolution10 g/15mLoralPharmaceutical Associates, Inc,1966-07-30Not AvailableUs 0a2ef1ad1c84951dc1392a8bbe1f3cb241c91ed59e44ad8268635315440d978c
Lactulosesolution10 g/15mLoralPharmaceutical Associates, Inc,1966-07-30Not AvailableUs 0a2ef1ad1c84951dc1392a8bbe1f3cb241c91ed59e44ad8268635315440d978c
Lactulosesolution10 g/15mLoralQualitest Pharmaceuticals2001-07-26Not AvailableUs 0a2ef1ad1c84951dc1392a8bbe1f3cb241c91ed59e44ad8268635315440d978c
Lactulosesolution10 g/15mLoralAtlantic Biologicals Corps2001-07-26Not AvailableUs 0a2ef1ad1c84951dc1392a8bbe1f3cb241c91ed59e44ad8268635315440d978c
Lactulosesolution10 g/15mLoralRebel Distributors Corp2004-04-19Not AvailableUs 0a2ef1ad1c84951dc1392a8bbe1f3cb241c91ed59e44ad8268635315440d978c
Lactulosesolution10 g/15mLoralLake Erie Medical DBA Quality Care Products LLC2001-07-26Not AvailableUs 0a2ef1ad1c84951dc1392a8bbe1f3cb241c91ed59e44ad8268635315440d978c
Enulosesolution10 g/15mLoral; rectalActavis Inc.2011-02-28Not AvailableUs 0a2ef1ad1c84951dc1392a8bbe1f3cb241c91ed59e44ad8268635315440d978c
Constulosesolution10 g/15mLoralActavis Inc.2011-02-28Not AvailableUs 0a2ef1ad1c84951dc1392a8bbe1f3cb241c91ed59e44ad8268635315440d978c
Lactulosesolution10 g/15mLoralLake Erie Medical & Surgical Supply DBA Quality Care Products LLC2004-04-19Not AvailableUs 0a2ef1ad1c84951dc1392a8bbe1f3cb241c91ed59e44ad8268635315440d978c
Lactulosesolution10 g/15mLoralHi Tech Pharmacal Co., Inc.1995-07-03Not AvailableUs 0a2ef1ad1c84951dc1392a8bbe1f3cb241c91ed59e44ad8268635315440d978c
Lactulosesolution10 g/15mLoral; rectalHi Tech Pharmacal Co., Inc.1995-07-03Not AvailableUs 0a2ef1ad1c84951dc1392a8bbe1f3cb241c91ed59e44ad8268635315440d978c
Lactulosesolution10 g/15mLoralUnit Dose Services1995-07-03Not AvailableUs 0a2ef1ad1c84951dc1392a8bbe1f3cb241c91ed59e44ad8268635315440d978c
Lactulosesolution10 g/15mLoralAidarex Pharmaceuticals LLC1995-07-03Not AvailableUs 0a2ef1ad1c84951dc1392a8bbe1f3cb241c91ed59e44ad8268635315440d978c
Lactulosesolution10 g/15mLoralPhysicians Total Care, Inc.2004-04-19Not AvailableUs 0a2ef1ad1c84951dc1392a8bbe1f3cb241c91ed59e44ad8268635315440d978c
Lactulosesolution20 g/30mLoralCardinal Health2010-05-10Not AvailableUs 0a2ef1ad1c84951dc1392a8bbe1f3cb241c91ed59e44ad8268635315440d978c
Lactulosesolution10 g/15mLoralCardinal Health1996-07-30Not AvailableUs 0a2ef1ad1c84951dc1392a8bbe1f3cb241c91ed59e44ad8268635315440d978c
Lactulosesolution10 g/15mLoralCardinal Health1966-07-30Not AvailableUs 0a2ef1ad1c84951dc1392a8bbe1f3cb241c91ed59e44ad8268635315440d978c
Lactulosesolution10 g/15mLoralMorton Grove Pharmaceuticals, Inc.1996-11-14Not AvailableUs 0a2ef1ad1c84951dc1392a8bbe1f3cb241c91ed59e44ad8268635315440d978c
Generlacsolution10 g/15mLoralMorton Grove Pharmaceuticals, Inc.1996-10-31Not AvailableUs 0a2ef1ad1c84951dc1392a8bbe1f3cb241c91ed59e44ad8268635315440d978c
Lactulosesolution10 g/15mLoral; rectalApotex Corp.2005-01-26Not AvailableUs 0a2ef1ad1c84951dc1392a8bbe1f3cb241c91ed59e44ad8268635315440d978c
Lactulosesolution10 g/15mLoralMc Kesson Packaging Services A Business Unit Of Mc Kesson Corporation2011-11-01Not AvailableUs 0a2ef1ad1c84951dc1392a8bbe1f3cb241c91ed59e44ad8268635315440d978c
Kristalosepowder, for solution10 g/10goralCumberland Pharmaceuticals Inc.2012-01-20Not AvailableUs 0a2ef1ad1c84951dc1392a8bbe1f3cb241c91ed59e44ad8268635315440d978c
Kristalosepowder, for solution20 g/20goralCumberland Pharmaceuticals Inc.2012-01-20Not AvailableUs 0a2ef1ad1c84951dc1392a8bbe1f3cb241c91ed59e44ad8268635315440d978c
Lactulosesolution20 g/30mLoralVista Pharm, Inc2010-05-10Not AvailableUs 0a2ef1ad1c84951dc1392a8bbe1f3cb241c91ed59e44ad8268635315440d978c
Lactulosesolution10 g/15mLoralVista Pharm, Inc2010-05-10Not AvailableUs 0a2ef1ad1c84951dc1392a8bbe1f3cb241c91ed59e44ad8268635315440d978c
Over the Counter Products
NameDosageStrengthRouteLabellerMarketing StartMarketing End
Lactulosesyrup667 mgoralSanis Health IncNot AvailableNot AvailableCanada 5f16b84899037e23705f146ff57e3794121879cb055f0954756d94bc690476b4
International Brands
CephulacNot Available
ChronulacNot Available
Brand mixturesNot Available
SaltsNot Available
CAS number4618-18-2
WeightAverage: 342.2965
Monoisotopic: 342.116211546
Chemical FormulaC12H22O11
DescriptionThis compound belongs to the class of organic compounds known as o-glycosyl compounds. These are glycoside in which a sugar group is bonded through one carbon to another group via a O-glycosidic bond.
KingdomOrganic compounds
Super ClassOrganooxygen compounds
ClassCarbohydrates and carbohydrate conjugates
Sub ClassGlycosyl compounds
Direct ParentO-glycosyl compounds
Alternative Parents
  • O-glycosyl compound
  • Disaccharide
  • C-glycosyl compound
  • Oxane
  • Oxolane
  • Secondary alcohol
  • Polyol
  • Hemiacetal
  • 1,2-diol
  • Oxacycle
  • Organoheterocyclic compound
  • Acetal
  • Hydrocarbon derivative
  • Primary alcohol
  • Alcohol
  • Aliphatic heteromonocyclic compound
Molecular FrameworkAliphatic heteromonocyclic compounds
External Descriptors
IndicationFor the treatment of constipation and hepatic encephalopathy.
PharmacodynamicsTherapeutically, lactulose has laxative and ammonia-detoxifying actions. In treating constipation lactulose metabolites draw water into the bowel, causing a cathartic effect through osmotic action.
Mechanism of actionLactulose is a synthetic sugar used in the treatment of constipation and liver disease. It consists of the monosaccharides fructose and galactose. In the colon, lactulose is broken down primarily to lactic acid, and also to small amounts of formic and acetic acids, by the action of via evolved-beta galactosidase from colonic bacteria, which results in an increase in osmotic pressure and slight acidification of the colonic contents. This in turn causes an increase in stool water content and softens the stool. In treating heptic diseases (hepatic encephalopathy) it is thought that lactulose draws out ammonia from the body in the same way that it draws out water into the colon.
AbsorptionPoorly absorbed from the gastrointestinal tract as no human enzyme that is capable of hydrolysis of this disaccharide is present in human gastrointestinal tissue.
Volume of distributionNot Available
Protein bindingNot Available

Lactulose is completely metabolized in the colon by enteric bacteria, and no lactulose is excreted in the feces.

Route of eliminationThe primary route of elimination is fecal. Urinary excretion has been determined to be 3% or less and is essentially complete within 24 hours.
Half life1.7-2 hours
ClearanceNot Available
ToxicityLD50=18.2 g/kg (oral, rat). Side effects include diarrhea and resultant dehydration.
Affected organisms
  • Humans and other mammals
PathwaysNot Available
SNP Mediated EffectsNot Available
SNP Mediated Adverse Drug ReactionsNot Available
Predicted ADMET features
Human Intestinal Absorption-0.8407
Blood Brain Barrier+0.6609
Caco-2 permeable-0.8957
P-glycoprotein substrateNon-substrate0.5805
P-glycoprotein inhibitor INon-inhibitor0.8575
P-glycoprotein inhibitor IINon-inhibitor0.9425
Renal organic cation transporterNon-inhibitor0.849
CYP450 2C9 substrateNon-substrate0.8745
CYP450 2D6 substrateNon-substrate0.854
CYP450 3A4 substrateNon-substrate0.6605
CYP450 1A2 substrateNon-inhibitor0.9472
CYP450 2C9 substrateNon-inhibitor0.9556
CYP450 2D6 substrateNon-inhibitor0.9386
CYP450 2C19 substrateNon-inhibitor0.9134
CYP450 3A4 substrateNon-inhibitor0.9774
CYP450 inhibitory promiscuityLow CYP Inhibitory Promiscuity0.9619
Ames testNon AMES toxic0.9421
BiodegradationNot ready biodegradable0.6719
Rat acute toxicity1.2563 LD50, mol/kg Not applicable
hERG inhibition (predictor I)Weak inhibitor0.9692
hERG inhibition (predictor II)Non-inhibitor0.8684
  • Inalco spa
  • Sanofi aventis us llc
  • Alra laboratories inc
  • Actavis mid atlantic llc
  • Solvay pharmaceuticals
  • Teva pharmaceuticals usa
  • Ani pharmaceuticals inc
  • Hi tech pharmacal co inc
  • Morton grove pharmaceuticals inc
  • Novex pharma
  • Paco pharmaceutical services inc
  • Pharmaceutical assoc inc div beach products
  • Roxane laboratories inc
  • Vintage pharmaceuticals inc
  • Vistapharm inc
  • Nostrum laboratories inc
Dosage forms
Powder, for solutionoral10 g/10g
Powder, for solutionoral20 g/20g
Solutionoral10 g/15mL
Solutionoral20 g/30mL
Solutionoral; rectal10 g/15mL
Syruporal667 mg
Unit descriptionCostUnit
Kristalose 30 20 gm Packets Box83.93USD box
Kristalose 30 10 gm Packets Box57.57USD box
Enulose 10 gm/15ml Solution 473ml Bottle37.83USD bottle
Kristalose 20 gm packet2.04USD each
Kristalose 10 gm packet1.67USD each
Constulose 10 gm/15 ml soln0.09USD ml
Enulose 10 gm/15 ml solution0.08USD ml
Lactulose Encephalopathy 10 gm/15ml Solution0.08USD ml
Lactulose 10 gm/15ml Solution0.07USD ml
Generlac 10 gm/15 ml solution0.05USD ml
Apo-Lactulose 667 mg/ml Syrup0.02USD ml
Jamp-Lactulose 667 mg/ml Syrup0.02USD ml
Pms-Lactulose 667 mg/ml Syrup0.02USD ml
Ratio-Lactulose 667 mg/ml Syrup0.02USD ml
DrugBank does not sell nor buy drugs. Pricing information is supplied for informational purposes only.
PatentsNot Available
Experimental Properties
melting point169 °CPhysProp
water solubility7.64E+005 mg/L (at 30 °C)MERCK (1989)
logP-4.3Not Available
Predicted Properties
Water Solubility792.0 mg/mLALOGPS
pKa (Strongest Acidic)10.28ChemAxon
pKa (Strongest Basic)-3ChemAxon
Physiological Charge0ChemAxon
Hydrogen Acceptor Count11ChemAxon
Hydrogen Donor Count8ChemAxon
Polar Surface Area189.53 Å2ChemAxon
Rotatable Bond Count5ChemAxon
Refractivity68.77 m3·mol-1ChemAxon
Polarizability31.49 Å3ChemAxon
Number of Rings2ChemAxon
Rule of FiveYesChemAxon
Ghose FilterYesChemAxon
Veber's RuleYesChemAxon
MDDR-like RuleYesChemAxon
Mass Spec (NIST)Not Available
SpectraNot Available
Synthesis Reference

Renato Carobbi, Franco Innocenti, “Process for preparing high-purity lactulose syrup and the syrup obtained.” U.S. Patent US4978397, issued April, 1961.

General ReferenceNot Available
External Links
ATC CodesA06AD11
AHFS Codes
  • 40:10.00
PDB EntriesNot Available
FDA labelNot Available
MSDSDownload (73.6 KB)
Drug InteractionsNot Available
Food InteractionsNot Available


1. Evolved beta-galactosidase subunit alpha

Kind: protein

Organism: Escherichia coli (strain K12)

Pharmacological action: yes

Actions: other


Name UniProt ID Details
Evolved beta-galactosidase subunit alpha P06864 Details


  1. Overington JP, Al-Lazikani B, Hopkins AL: How many drug targets are there? Nat Rev Drug Discov. 2006 Dec;5(12):993-6. Pubmed
  2. Imming P, Sinning C, Meyer A: Drugs, their targets and the nature and number of drug targets. Nat Rev Drug Discov. 2006 Oct;5(10):821-34. Pubmed
  3. Bjarnason I, Batt R, Catt S, Macpherson A, Maxton D, Menzies IS: Evaluation of differential disaccharide excretion in urine for non-invasive investigation of altered intestinal disaccharidase activity caused by alpha-glucosidase inhibition, primary hypolactasia, and coeliac disease. Gut. 1996 Sep;39(3):374-81. Pubmed
  4. Cook GC: Breath hydrogen concentrations after oral lactose and lactulose in tropical malabsorption and adult hypolactasia. Trans R Soc Trop Med Hyg. 1978;72(3):277-81. Pubmed
  5. Noone C, Menzies IS, Banatvala JE, Scopes JW: Intestinal permeability and lactose hydrolysis in human rotaviral gastroenteritis assessed simultaneously by non-invasive differential sugar permeation. Eur J Clin Invest. 1986 Jun;16(3):217-25. Pubmed
  6. Hall BG, Malik HS: Determining the evolutionary potential of a gene. Mol Biol Evol. 1998 Aug;15(8):1055-61. Pubmed

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Drug created on June 13, 2005 07:24 / Updated on September 16, 2013 17:11