This drug is used by mouth or rectally to treat or prevent complications of liver disease (hepatic encephalopathy). It does not cure the problem, but may help to improve mental status. Lactulose is a colonic acidifier that works by decreasing the amount of ammonia in the blood. It is a man-made sugar solution.

This section contains uses of this drug that are not listed in the approved professional labeling for the drug, but may be prescribed by your health care professional. Use this drug for a condition that is listed in this section only if has been so prescribed by your health care professional.

The form of this drug that is taken by mouth may also be used for constipation.

If you are taking this medication by mouth for liver disease, take it as directed by your doctor, usually 3 to 4 times a day. To improve the taste, you may mix it into fruit juice, water, milk, or a soft dessert. The goal is to have 2 to 3 soft stools each day. The dosage is based on your medical condition and response to treatment (for example, the number of soft stools each day).

If you are taking this medication by mouth for constipation, take it as directed by your doctor, usually once daily.

This medication can also be given rectally as an enema for liver disease. Mix the recommended amount of lactulose with 700 milliliters (24 ounces) of water or normal saline. Give the solution into the rectum and keep the liquid inside for 30 to 60 minutes as directed by your doctor. If you keep the enema inside for less than 30 minutes, repeat the dose unless directed otherwise.

Use this medication regularly in order to get the most benefit from it. Remember to use it at the same time each day.

When this drug is given rectally for liver disease, an improvement in your mental status may occur in as little as 2 hours, but if you are taking this medication by mouth, it may take up to 24 to 48 hours. If you are using this medication for constipation, it may take up to 48 hours to have a bowel movement. Tell your doctor if your condition lasts or gets worse.

Gas, bloating, burping, stomach rumbling/pain, nausea, and cramps may occur. If any of these effects last or get worse, tell your doctor or pharmacist promptly.

Remember that this medication has been prescribed because your doctor has judged that the benefit to you is greater than the risk of side effects. Many people using this medication do not have serious side effects.

Tell your doctor right away if you have any serious side effects, including:

• diarrhea
• vomiting
• muscle cramps/weakness
• irregular heartbeat
• mental/mood changes
• seizures

A very serious allergic reaction to this drug is rare. However, get medical help right away if you notice any symptoms of a serious allergic reaction, including:

• rash
• itching/swelling (especially of the face/tongue/throat)
• severe dizziness
• trouble breathing

This is not a complete list of possible side effects. If you notice other effects not listed above, contact your doctor or pharmacist.

In the US - Call your doctor for medical advice about side effects. You may report side effects to FDA at 1-800-FDA-1088 or at www.fda.gov/medwatch.

In Canada - Call your doctor for medical advice about side effects. You may report side effects to Health Canada at 1-866-234-2345.

Before using lactulose, tell your doctor or pharmacist if you are allergic to it; or if you have any other allergies. This product may contain inactive ingredients, which can cause allergic reactions or other problems. Talk to your pharmacist for more details.

Before using this medication, tell your doctor or pharmacist your medical history, especially of:

• a low galactose diet (such as a diet that includes few or no milk products)
• certain other bowel problem (bowel obstruction)
• diabetes

Before having surgery, tell your doctor or dentist about all the products you use (including prescription drugs, nonprescription drugs, and herbal products).

This medication contains different sugars. If you have diabetes, this medication may affect your blood sugar. Check your blood sugar regularly as directed and share the results with your doctor. Your doctor may need to adjust your diabetes medication, exercise program, or diet.

During pregnancy, this medication should be used only when clearly needed. Discuss the risks and benefits with your doctor.

It is unknown if this drug passes into breast milk. Consult your doctor before breastfeeding.

Drug interactions may change how your medications work or increase your risk for serious side effects. This document does not contain all possible drug interactions. Keep a list of all the products you use (including prescription/nonprescription drugs and herbal products) and share it with your doctor and pharmacist. Do not start, stop, or change the dosage of any medicines without your doctor's approval.

Some products that may interact with this drug are:

• antacids containing aluminum and/or magnesium
• other laxatives (such as cleansing enemas with soap suds)

If someone has overdosed and has serious symptoms such as passing out or trouble breathing, call 911. Otherwise, call a poison control center right away. US residents can call 1-800-222-1222. Canada residents can call 1-844-764-7669. Symptoms of overdose may include: severe stomach cramps, diarrhea.

If you are using this medication for liver disease, your doctor may direct you to follow a low-protein diet. Follow any dietary guidelines recommended by your doctor or dietician.

Do not share this product with others.

If you use this product for a long time, lab and/or medical tests (such as blood mineral levels) should be done while you are using this medication. Keep all medical and lab appointments. Consult your doctor for more details.

If you miss a dose, take it as soon as you remember. If it is near the time of the next dose, skip the missed dose. Take your next dose at the regular time. Do not double the dose to catch up.

Different brands of this medication have different storage needs. Check the product package for instructions on how to store your brand, or ask your pharmacist. Keep all medications away from children and pets.

Do not flush medications down the toilet or pour them into a drain unless instructed to do so. Properly discard this product when it is expired or no longer needed. Consult your pharmacist or local waste disposal company.