Generic name: lactulose (oral) (LAK too lose)
Brand name: Constulose, Kristalose, Chronulac, Cephulac, Constilac, Cholac, Duphalac, Evalose, Heptalac, Enulose, Generlac
Dosage forms: oral powder for reconstitution (10 g; 20 g); oral syrup (10 g/15 mL); oral and rectal liquid (10 g/15 mL)
Drug class: Laxatives
Lactulose is a type of sugar. It is broken down in the large intestine into mild acids that draw water into the colon, which helps soften the stools.
Lactulose is used to treat chronic constipation.
Lactulose is sometimes used to treat or prevent certain conditions of the brain that are caused by liver failure, which can lead to confusion, problems with memory or thinking, behavior changes, tremors, feeling irritable, sleep problems, loss of coordination, and loss of consciousness.
Lactulose may also be used for purposes not listed in this medication guide.
Warnings
You should not use this medication if you are on a special diet low in galactose (milk sugar).
Before taking lactulose, tell your doctor if you have diabetes or if you need to have any type of intestinal test using a scope (such as a colonoscopy).
It may take up to 48 hours before you have a bowel movement after taking lactulose.
Stop using lactulose and call your doctor at once if you have severe or ongoing diarrhea.
The liquid form of lactulose may become slightly darker in color, but this is a harmless effect. However, do not use the medicine if it becomes very dark, or if it gets thicker or thinner in texture.
If you use lactulose over a long period of time, your doctor may want you to have occasional blood tests. Do not miss any scheduled appointments.
Before taking this medicine
You should not use this medication if you are on a special diet low in galactose (milk sugar).
To make sure you can safely take lactulose, tell your doctor if you have other medical conditions, especially:
- diabetes; or
- if you need to have any type of intestinal test using a scope (such as a colonoscopy).
FDA pregnancy category B. This medication is not expected to be harmful to an unborn baby. Tell your doctor if you are pregnant or plan to become pregnant during treatment.
It is not known whether lactulose passes into breast milk or if it could harm a nursing baby. Do not use this medication without telling your doctor if you are breast-feeding a baby.
How should I take lactulose?
Take exactly as prescribed by your doctor. Do not take in larger or smaller amounts or for longer than recommended. Follow the directions on your prescription label.
Measure liquid medicine with a special dose-measuring spoon or cup, not a regular table spoon. If you do not have a dose-measuring device, ask your pharmacist for one.
The liquid form of lactulose may become slightly darker in color, but this is a harmless effect. However, do not use the medicine if it becomes very dark, or if it gets thicker or thinner in texture.
Lactulose powder should be mixed with at least 4 ounces of water. You may also use fruit juice or milk to make the medication taste better.
It may take up to 48 hours before you have a bowel movement after taking lactulose.
If you use lactulose over a long period of time, your doctor may want you to have occasional blood tests. Do not miss any scheduled appointments.
Store lactulose at room temperature away from moisture and heat.
What happens if I miss a dose?
Take the missed dose as soon as you remember. Skip the missed dose if it is almost time for your next scheduled dose. Do not take extra medicine to make up the missed dose.
What happens if I overdose?
Seek emergency medical attention or call the Poison Help line at 1-800-222-1222.
Overdose symptoms may include confusion, uneven heart rate, extreme thirst, increased urination, leg discomfort, and muscle weakness or limp feeling.
What should I avoid while taking lactulose?
Avoid using antacids without your doctor's advice. Use only the type of antacid your doctor recommends. Some antacids can make it harder for your body to absorb lactulose.
Lactulose side effects
Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficult breathing; swelling of your face, lips, tongue, or throat.
Stop using lactulose and call your doctor at once if you have severe or ongoing diarrhea.
Less serious side effects may include:
- bloating, gas;
- stomach pain;
- diarrhea; or
- nausea, vomiting.
This is not a complete list of side effects and others may occur. Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088.
Lactulose dosing information
Usual Adult Dose for Constipation -- Chronic:
15 mL orally once a day.
Usual Adult Dose for Constipation -- Acute:
Initial dose: 15 mL orally once a day. Therapy should be continued until normal bowel function resumes.
Usual Adult Dose for Hepatic Encephalopathy:
Initial dose: 30 mL orally 3 times a day or
300 mL in 700 mL water or normal saline as an enema retained for 30 to 60 minutes every 4 to 6 hours.
Maintenance dose: 30 to 45 mL orally 3 times a day.
Usual Pediatric Dose for Hepatic Encephalopathy:
Infants: 1.7 to 6.7 g/day (2.5 to 10 mL) orally daily divided in 3 to 4 doses. Adjust dosage to produce 2 to 3 soft stools per day.
Children: 26.7 to 60 g/day (40 to 90 mL) orally daily divided in 3 to 4 doses. Adjust dosage to produce 2 to 3 soft stools per day.
Usual Pediatric Dose for Constipation -- Chronic:
Children: 0.7 to 2 g/kg/day (1 to 3 mL/kg/day) orally in divided doses daily; generally recommended not to exceed the adult maximum of 40 g/day (60 mL/day).
What other drugs will affect lactulose?
There may be other drugs that can interact with lactulose. Tell your doctor about all medications you use. This includes prescription, over-the-counter, vitamin, and herbal products. Do not start a new medication without telling your doctor.