Medically reviewed by Drugs.com. Last updated on Aug 22, 2023.

Generic Name: lactulose (LAK too lose)
Brand Names: Duphalac, Enulose, Generlac, Kristalose

What is Duphalac?

Duphalac 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.

Duphalac is used to treat chronic constipation.

Duphalac may also be used for other purposes not listed in this medication guide.

What is the most important information I should know about Duphalac?

You should not use this medication if you are on a special diet low in galactose (milk sugar).

Before taking Duphalac, 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 this medicine.

Stop using Duphalac and call your doctor at once if you have severe or ongoing diarrhea.

The liquid form of Duphalac 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 Duphalac over a long period of time, your doctor may want you to have occasional blood tests. Do not miss any scheduled appointments.

What should I discuss with my healthcare provider before taking Duphalac?

You should not use this medication if you are on a special diet low in galactose (milk sugar).

Before taking Duphalac, 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).

If you have any of these conditions, you may need a dose adjustment or special tests to safely take Duphalac.

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 Duphalac 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 Duphalac?

Take this medication exactly as prescribed by your doctor. Do not take it in larger 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 Duphalac 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.

Duphalac (lactulose) powder should be mixed with at least 4 ounces of water. You may also use fruit juice or milk to make the medication better.

It may take up to 48 hours before you have a bowel movement after taking this medicine.

If you use Duphalac over a long period of time, your doctor may want you to have occasional blood tests. Do not miss any scheduled appointments.

Store Duphalac at room temperature away from moisture and heat.

Related/similar drugs

MiraLAX, lactulose, Xifaxan, polyethylene glycol 3350, rifaximin, neomycin, polyethylene glycol 3350 with electrolytes, Movantik, GoLYTELY, Relistor

What happens if I miss a dose?

Take the missed dose as soon as you remember. If it is almost time for your next dose, wait until then to take the medicine and skip the missed dose. Do not take extra medicine to make up the missed dose.

What happens if I overdose?

Seek emergency medical attention if you think you have used too much of this medicine.

Overdose symptoms may include diarrhea, stomach pain, hot and dry skin, confusion, uneven heart rate, extreme thirst, increased urination, leg discomfort, and muscle weakness or limp feeling.

What to avoid

Avoid using antacids without your doctor's advice. Use only the specific type of antacid your doctor recommends. Antacids contain different medicines and some types can make it harder for your body to absorb Duphalac.

Duphalac (lactulose) side effects

Get emergency medical help if you have any of these signs of an allergic reaction: hives; difficulty breathing; swelling of your face, lips, tongue, or throat. Stop using Duphalac 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. Tell your doctor about any unusual or bothersome side effect.

What other drugs will affect Duphalac?

There may be other drugs that can interact with Duphalac. Tell your doctor about all your prescription and over-the-counter medications, vitamins, minerals, herbal products, and drugs prescribed by other doctors. Do not start a new medication without telling your doctor.

Further information

• Remember, keep this and all other medicines out of the reach of children, never share your medicines with others, and use this medication only for the indication prescribed.
• Disclaimer: Every effort has been made to ensure that the information provided by Cerner Multum, Inc. ('Multum') is accurate, up-to-date, and complete, but no guarantee is made to that effect. Drug information contained herein may be time sensitive. Multum information has been compiled for use by healthcare practitioners and consumers in the United States and therefore Multum does not warrant that uses outside of the United States are appropriate, unless specifically indicated otherwise. Multum's drug information does not endorse drugs, diagnose patients or recommend therapy. Multum's drug information is an informational resource designed to assist licensed healthcare practitioners in caring for their patients and/or to serve consumers viewing this service as a supplement to, and not a substitute for, the expertise, skill, knowledge and judgment of healthcare practitioners. The absence of a warning for a given drug or drug combination in no way should be construed to indicate that the drug or drug combination is safe, effective or appropriate for any given patient. Multum does not assume any responsibility for any aspect of healthcare administered with the aid of information Multum provides. The information contained herein is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects. If you have questions about the drugs you are taking, check with your doctor, nurse or pharmacist.

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