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Lactulose oral

Important Note

The following information is intended to supplement, not substitute for, the expertise and judgment of your physician, pharmacist or other healthcare professional. It should not be construed to indicate that use of the drug is safe, appropriate, or effective for you. Consult your healthcare professional before using this drug.



COMMON BRAND NAME(S): Chronulac, Constilac, Constulose, Duphalac, Evalose


This medication is a laxative used to treat constipation.



Lactulose may also be used to treat and prevent complications of liver disease (hepatic encephalopathy).

How To Use

This medication is taken by mouth. To improve the taste, the dose may be mixed in a glass of fruit juice, water or milk. Take this medication as prescribed.

Side Effects

This medication may cause gas, belching or stomach cramps. If these effects continue or become bothersome, inform your doctor. Notify your doctor if you develop any of these effects while taking this medication: diarrhea, nausea, vomiting. If you notice other effects not listed above, contact your doctor or pharmacist.


This medication must be used cautiously in children and the elderly. If diarrhea results, notify your doctor. A dosage adjustment may be necessary. Do not take any other laxative medications while taking this drug. Frequent or excessive use of laxatives can cause dehydration. Symptoms include: muscle weakness, muscle cramps, dizziness. This medication must be used only if clearly needed during pregnancy. Discuss the risks and benefits with your doctor. It is not known if this medication appears in breast milk. Consult with your doctor before breast-feeding. This medication contains galactose and lactose. Be sure to tell your doctor if you have diabetes.

Drug Interactions

Tell your doctor of all prescription and nonprescription drugs you may use, especially of: antibiotics (e.g., neomycin), antacids, other laxatives. Do not start or stop any medicine without doctor or pharmacist approval.


If overdose is suspected, contact your local poison control center or emergency room immediately. Symptoms of overdose may include stomach cramps and diarrhea.


Do not share this product with others.

Missed Dose

If you miss a dose, use it as soon as remembered; do not use if it is almost time for the next dose, instead, skip the missed dose and resume your usual dosing schedule. Do not "double-up" the dose to catch up.


Store at room temperature away from sunlight and moisture. Avoid freezing.