Lactulose (By mouth)

Lactulose (LAK-tue-lose)

Treats constipation.

Brand Name(s):

Constulose, Enulose, Generlac

There may be other brand names for this medicine.

When This Medicine Should Not Be Used:

This medicine is not right for everyone. Do not use it if you are following a diet low in lactose or galactose.

How to Use This Medicine:

Liquid

  • Take your medicine as directed. Your dose may need to be changed several times to find what works best for you.
  • Oral liquid:
    • Measure the oral liquid medicine with a marked measuring spoon, oral syringe, or medicine cup.
    • You may mix it with water, milk, or fruit juice.
  • Powder for solution: Mix the entire contents of the packet in half a glass (4 ounces) of water until solution is colorless to a slightly pale yellow color.
  • It may take 24 to 48 hours before you have a normal bowel movement.
  • Missed dose: Take a dose as soon as you remember. If it is almost time for your next dose, wait until then and take a regular dose. Do not take extra medicine to make up for a missed dose.
  • Store the medicine in a closed container at room temperature, away from heat, moisture, and direct light.

Drugs and Foods to Avoid:

Ask your doctor or pharmacist before using any other medicine, including over-the-counter medicines, vitamins, and herbal products.

  • Some medicines can affect how lactulose works. Tell your doctor if you are using antacids.

Warnings While Using This Medicine:

  • Tell your doctor if you are pregnant or breastfeeding, or if you have diabetes.
  • Tell your doctor that you are taking lactulose before you have any medical tests or surgery on your colon or rectum.
  • Your doctor will check your progress and the effects of this medicine at regular visits. Keep all appointments.
  • Keep all medicine out of the reach of children. Never share your medicine with anyone.

Possible Side Effects While Using This Medicine:

Call your doctor right away if you notice any of these side effects:

  • Allergic reaction: Itching or hives, swelling in your face or hands, swelling or tingling in your mouth or throat, chest tightness, trouble breathing
  • Confusion, weakness, muscle twitching
  • Dry mouth, increased thirst, muscle cramps, nausea or vomiting, fast or uneven heartbeat
  • Severe diarrhea

If you notice these less serious side effects, talk with your doctor:

  • Passing gas, stomach cramps

If you notice other side effects that you think are caused by this medicine, tell your doctor

Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088


Last Updated: 9/6/2024

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