Lactulose (Duphalac Syrup) is an osmotic laxative that relieves constipation. It is also used to treat patients with hepatic encephalopathy (portosystemic encephalopathy) by converting ammonia to ammonium ion.

Lactulose Uses:

• Constipation (Constulose, Kristalose):

  • It is primarily used to treat constipation.

• Portal systemic encephalopathy (Enulose, Generlac):

  • It is indicated for the prevention and treatment of portal-systemic encephalopathy (including hepatic precoma and coma)

• Off Label Use of Lactulose in Adults:

  • It is indicated for minimal hepatic encephalopathy

Read: Rifaximin for hepatic encephalopathy

Lactulose (Duphalac Syrup) Dose in Adults:

Lactulose (Duphalac Syrup) Dose in the treatment of Constipation:

• 10 to 20 g (15 to 30 mL or 1 to 2 packets) orally daily in divided doses;
• The dose may be increased to 40 g (60 mL or 2 to 4 packets) daily if required.

Lactulose (Duphalac Syrup) Dose in the prevention of Portal systemic encephalopathy (PSE):

• 20 to 30 g (30 to 45 mL) orally 3 to 4 times a day.
• The dose is adjusted every 1 to 2 days to produce 2 to 3 soft stools/day

Lactulose (Duphalac Syrup) Dose in the treatment of PSE:

• 20 to 30 g (30 to 45 mL) orally every one hour to induce a rapid laxative effect.
• The dose may be reduced to 20 to 30 g (30 to 45 mL) 3 to 4 times a day after a laxative effect is achieved to produce 2 to 3 soft stools/day.

Rectal administration (retention enema):

• 200 g (300 mL) is administered via a rectal balloon catheter.
• The enema is retained for 30 to 60 minutes.
• The dose may be repeated every 4 to 6 hours;
• Transition to oral treatment before discontinuing rectal administration

Lactulose (Duphalac Syrup) Dose in the treatment of Overt hepatic encephalopathy (OHE) episodes,:

• Route not specified:

  • 7 g (25 mL) every 1 to 2 hours until at least 2 soft or loose bowel movements are produced per day.
  • The dose may be titrated to maintain 2 to 3 bowel movements per day.

Lactulose (Duphalac Syrup) Dose in the treatment of Minimal hepatic encephalopathy (off-label):

• 20 to 40 g (30 to 60 mL) per day in 2 to 3 divided doses to maintain 2 to 3 bowel movements daily for up to three months.

Lactulose (Duphalac Syrup) Dose in Childrens:

Note: Doses in children may be expressed in volume (mL) or weight (g); Extra precautions must be taken.

Lactulose (Duphalac Syrup) Dose in the treatment of chronic Constipation: Limited data available:

• Infants, Children, and Adolescents:

  • 1 to 2 g/kg/day (1.5 to 3 mL/kg/day) orally in one or two divided doses.
  • The maximum daily dose is 60 mL/day in adults.

Lactulose (Duphalac Syrup) Dose in the treatment of Constipation, palliative care: Limited data available:

• Children and Adolescents:

  • 2 to 30 mL orally every 6 to 24 hours.

Lactulose (Duphalac Syrup) Dose in the treatment of Fecal impaction, slow disimpaction: Limited data available:

• Infants, Children, and Adolescents:

  • Oral: 1.33 g/kg/dose (2 mL/kg) two times a day for 7 days.

Lactulose (Duphalac Syrup) Dose in the prevention of Portal systemic encephalopathy: Oral liquid:

• Infants:

  • 7 to 6.7 g/day (2.5 to 10 mL/day) in divided doses;
  • Adjust the dose to produce 2 to 3 stools/day.

• Children and Adolescents:

  • 7 to 60 g/day (40 to 90 mL/day) in divided doses;
  • Adjust the dosage to produce 2 to 3 stools/day

Pregnancy Risk Factor B

• Lactulose is poorly absorbed by the gastrointestinal tract. 
• Oral administration has been associated with adverse pregnancy outcomes in animals.
• Fiber and bulk-forming laxatives should be considered the first-line treatment for pregnant women. 
• Lactulose can be used during pregnancy for a brief time.

Breastfeeding

• It is not known if breastmilk will absorb the drug.
• While it is not well absorbed by the body systemically, the manufacturer recommends that lactating moms use it with caution.

Dose in Kidney Disease:

There are no dosage adjustments provided in the manufacturer’s labeling.

Dose in Liver disease:

There are no dosage adjustments provided in the manufacturer’s labeling.

Side effects of Lactulose (Duphalac Syrup):

• Endocrine & metabolic:

  • Dehydration
  • Hypernatremia
  • Hypokalemia

• Gastrointestinal:

  • Abdominal cramps
  • Abdominal distention
  • Abdominal distress
  • Diarrhea (excessive dose)
  • Eructation
  • Flatulence
  • Nausea
  • Vomiting

Contraindications to Lactulose (Duphalac Syrup):

• Low levels of galactose patients need to eat a low glycemic diet

Warnings & Precautions

• Inadequate electrolyte levels:

  • Long-term patients who have been receiving therapy for over 6 months could experience electrolyte imbalances. 
  • Debilitated and elderly people should be aware of electrolyte imbalances.
  • The presence of liver disease can lead to electrolyte imbalances. Hyponatremia can lead to infants becoming dehydrated.

• Diabetes:

  • Galactose, lactose, and insulin-dependent patients should be cautious when using the solution.

Lactulose: Drug Interaction

Monitoring parameters:

• Blood pressure, standing/supine;
• serum electrolytes,
• serum ammonia;
• bowel movement patterns,
• fluid status

How to administer Lactulose?

Oral solution:

• It may be mixed with fruit juice, water, or milk.

Crystals for oral solution:

• Dissolve the contents of the packet in 120 mL water.

Rectal:

• Dilute the solution with 700 mL of water or NS;
• Using a rectal balloon catheter, administer as retention enema;
• Retain the enema for 30 to 60 minutes.
• The dose may be repeated immediately if evacuated too promptly.
• Cleansing enemas that contain soapsuds or other alkaline agents should not be used.

Mechanism of action of Lactulose (Duphalac):

• Acidic pH is caused by bacteria in your stomach.Ammonia diffusion is inhibited by acidic pH.
• This converts ammonia NH3 into ammonium Ion(NH+4).
• It increases ammonia (NH3) diffusion to the blood and into the stomach, where it can be converted to ammonium.

Onset:

• Constipation: It takes up to 24 to 48 hours to produce a normal bowel movement
• Encephalopathy: At least 24 to 48 hours are required to lower the ammonia concentrations.

Absorption:

• It is poorly absorbed.

Metabolism:

• It is metabolized by the colonic flora to lactic acid and acetic acid.
• Colonic flora is required for drug activation

Excretion:

• Primarily feces;
• Urine (≤3%)

International Brands of Lactulose:

• Constulose
• Enulose
• Generlac
• Kristalose
• Actilax
• Alvolaxus
• Amivalex
• Avelac
• Bifiteral
• Biolac
• Comfort
• Constuloz
• Danilax
• Dhactulose
• Dia-Colon
• Dismam L
• Duphalac
• Extralac
• Ezilax
• Farcolac
• Farlac
• Genlac
• Genocolan
• Hepalac
• Lac-Dol
• Lacoly
• Lacson
• Lactocur
• Lactu
• Lactul
• Lactulax
• Lactulen
• Lactulon
• Lactulosa
• Lactulose-ratiopharm
• Lactumed
• Lactus
• Lactuverlan
• Laevolac
• Lagnos NF Jelly for Oral Administration
• Laktuvit
• Laxadilac
• Laxal
• Laxalan
• Laxette
• Laxiright
• Laxol
• Laxolac
• Laxolad
• Laxose
• Legendal
• Levolac
• Lidong
• Lilac
• Lipebin
• Livo Luk
• Livoluk
• Losalac
• Medilax
• Medulac
• Moderan
• Monilac
• Movelax
• Nophalac
• Normase
• Normolax
• Opilax
• Portalak
• Pralax
• Ramlac
• Regulact
• Rialac
• Rilax
• Sarex
• Sedalac
• Soflax
• Sorbilac
• Tenualax
• Ticolax
• Tulos
• Tulotract
• Veelac

Lactulose Brand Names in Pakistan: