Adult: As 3.335 g/5 mL solution: Initially, 30-45 mL 3-4 times daily, may be adjusted as necessary to achieve 2 or 3 soft stools daily.
Oral Constipation
Adult: As 3.335 g/5 mL solution or 10 g/15 mL single dose solution sachet: Initially, 15-45 mL (10-30 g or 1-3 sachets) daily, may be adjusted according to clinical response. Maintenance dose: 15-30 mL (10-20 g or 1-2 sachets) daily. All doses may be given as a single daily dose or in 2 divided doses. Therapeutic effect may occur after 2-3 days of treatment. As powder for solution: 10-20 g daily, may increase to 40 g daily if necessary. Child: <1 year As 3.335 g/5 mL solution: Initially, up to 5 mL daily. Maintenance dose: Up to 5 mL daily. 1-6 years As 3.335 g/5 mL solution: Initially, 5-10 mL daily. Maintenance dose: 5-10 mL daily. 7-14 years As 3.335 g/5 mL solution or 10 g/15 mL single dose solution sachet: Initially, 15 mL (10 g or 1 sachet) daily, may be adjusted according to clinical response. Maintenance dose: 10-15 mL (10 g or 1 sachet) daily. >14 years Same as adult dose. All doses may be given as a single daily dose or in 2 divided doses.
Rectal Hepatic encephalopathy
Adult: Mix 200 g (300 mL) of solution with 700 mL of water or 0.9% NaCl: Administer as a retention enema via balloon catheter over 30-60 minutes, may be repeated every 4-6 hourly depending on the response to treatment or until oral administration is possible.
Administration
May be taken with or without food. May be taken w/ meals to reduce GI discomfort. Dilute w/ water, milk, or fruit juice to improve taste.
Reconstitution
Powder for oral solution: Dissolve contents of a packet labelled as 10 g or 20 g in approx 120 mL of water. Refer to specific product guidelines.
Contraindications
Galactosaemia, gastrointestinal obstruction or subocclusive syndromes, acute inflammatory bowel disease (e.g. ulcerative colitis, Crohn's disease); existing or at risk of gastrointestinal perforation, painful abdominal syndromes of an unknown cause; patient requiring a low galactose diet.
Special Precautions
Patient with lactose intolerance, diabetes mellitus, gastro-cardiac syndrome (Roemheld syndrome); undergoing electrocautery procedures during proctoscopy or colonoscopy. Not recommended for use in patients with rare hereditary problems of galactose or fructose intolerance, the total lactase deficiency or glucose-galactose malabsorption. Reconsider dose and/or other additional measures if insufficient therapeutic effect is observed. Debilitated patients. Infants, children, and elderly. Pregnancy and lactation.
Drink sufficient amounts of fluids (1.5-2 L or 6-8 glasses daily).
Monitoring Parameters
Evaluate painful abdominal symptoms of an unknown cause prior to treatment initiation. Monitor blood pressure, serum electrolytes, serum ammonia, fluid status, and bowel movement frequency/consistency.
Overdosage
Symptoms: Diarrhoea, loss of electrolyte, abdominal pain. Management: Symptomatic treatment. Administer fluid and electrolyte replacement as necessary for extensive fluid loss caused by diarrhoea or vomiting.
Drug Interactions
May diminish the therapeutic effect with glutamine. May increase the risk of K loss caused by thiazides, corticosteroids, and amphotericin B. May increase the effects of cardiac glycosides. Non-absorbable antacids, neomycin, or other anti-infectives may cause a decrease in the desired effect of treatment with lactulose.
Action
Description: Lactulose, is a synthetic disaccharide osmotic laxative. Through bacterial degradation it is converted to low molecular organic acids; these acids cause a decrease of pH in the colonic lumen, and through an osmotic effect, an increase of the volume of colonic contents. Collectively, these effects cause peristalsis of the colon and the normalisation of stool consistency. In hepatic encephalopathy, its effect has been associated to the inhibition of proteolytic bacteria by an increase of acidophilic bacteria, trapping of ammonia in the ionic form through the acidification of the colonic contents, catharsis caused by the osmotic effect and the low pH in the colon, and the alteration of the bacterial nitrogen metabolism by promoting the utilisation of ammonia for bacterial protein synthesis. Onset: Constipation: Up to 24-48 hours. Hepatic encephalopathy: At least 24-48 hours. Pharmacokinetics: Absorption: Poorly absorbed from the gastrointestinal tract. Metabolism: Metabolised by colonic bacterial flora into low molecular organic acids (mainly lactic acid and small amounts of formic and acetic acids). Excretion: Mainly via faeces; urine (≤3% as unchanged drug).
Chemical Structure
Source: National Center for Biotechnology Information. PubChem Database. Lactulose, CID=11333, https://pubchem.ncbi.nlm.nih.gov/compound/Lactulose (accessed on Jan. 22, 2020)
Storage
Store between 15-30°C. Protect from light. Do not refrigerate or freeze.
A06AD11 - lactulose ; Belongs to the class of osmotically acting laxatives.
References
Anon. Lactulose. AHFS Clinical Drug Information [online]. Bethesda, MD. American Society of Health-System Pharmacists, Inc. https://www.ahfscdi.com. Accessed 08/03/2022.Anon. Lactulose. Lexicomp Online. Hudson, Ohio. Wolters Kluwer Clinical Drug Information, Inc. https://online.lexi.com. Accessed 08/03/2022.Buckingham R (ed). Lactulose. Martindale: The Complete Drug Reference [online]. London. Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 08/03/2022.Constulose Solution (Actavis Pharma, Inc.). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed. Accessed 08/03/2022.Duphalac (Mylan Products Ltd.). MHRA. https://products.mhra.gov.uk. Accessed 08/03/2022.Joint Formulary Committee. Lactulose. British National Formulary [online]. London. BMJ Group and Pharmaceutical Press. https://www.medicinescomplete.com. Accessed 08/03/2022.Kristalose Powder for Solution (Cumberland Pharmaceuticals Inc.). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed. Accessed 08/03/2022.Lactulose Solution (Fresenius Kabi Austria GmbH). DailyMed. Source: U.S. National Library of Medicine. https://dailymed.nlm.nih.gov/dailymed. Accessed 08/03/2022.Laevolac 10 g/15 mL Oral Solution Sachets (Fresenius Kabi Austria GmbH). MHRA. https://products.mhra.gov.uk. Accessed 08/03/2022.Nophalac Solution 670 mg/mL (Norpharma Sdn. Bhd.). MIMS Malaysia. http://www.mims.com/malaysia. Accessed 24/03/2022.Unilac (Kck Pharmaceutical Industries Sdn. Bhd.). MIMS Malaysia. http://www.mims.com/malaysia. Accessed 24/03/2022.
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