Lactulose

What lactulose is for

Lactulose is used to treat:

• constipation (problems pooing), such as not pooing very often or having poo that's dry and hard
• a liver condition called hepatic encephalopathy

Lactulose is a type of medicine called an osmotic laxative.

It works by bringing water into your bowel to help soften your poo and make it easier to push out.

How to take lactulose

Lactulose comes as a liquid (oral solution) that you drink.

How often and how long you take it for depends on why you're taking it. Always follow the advice your doctor or pharmacist gives you.

It can take 2 to 3 days to start working.

When taking lactulose:

• use the spoon or cup that comes with your medicine to measure the correct dose
• drink plenty of fluid to stay hydrated – being hydrated also helps with constipation
• try to take it at the same times each day and space the doses evenly
• you can take it with or without food
• you can add extra flavouring to make it taste nicer, such as squash

Always check the packet or leaflet that comes with your medicine. Ask a pharmacist or doctor for advice if you're not sure how to take it or have any problems taking it.

If you miss a dose of lactulose

If you forget to take a dose of lactulose, skip the dose you missed and take your next dose at the usual time.

Do not take 2 doses to make up for a missed dose.

If you take too much lactulose

Taking an extra dose of lactulose is unlikely to cause problems, but it's important to get medical advice if you take too much and feel unwell.

Side effects of lactulose

Like all medicines, lactulose can cause side effects, although not everyone gets them.

Common side effects

Common side effects of lactulose include:

• farting – this should ease after a few days
• bloating
• stomach ache
• feeling sick (nausea) or being sick (vomiting)
• diarrhoea

Lactulose does not usually affect your ability to drive, ride a bike or use machinery.

Serious side effects

Lactulose can sometimes cause serious side effects, although most of them are rare.

Possible serious side effects of lactulose include:

• an allergic reaction (anaphylaxis) – causing symptoms such as a swollen throat or tongue, a raised itchy rash and difficulty breathing
• low potassium in your blood, causing symptoms such as muscle weakness, tiredness, needing to pee a lot and heart rhythm problems – this can happen if you have frequent diarrhoea from taking too much lactulose for too long

Who can and cannot take lactulose

Most adults and children aged 14 years and over can take lactulose. Babies and children younger than 14 years can only have lactulose if it's prescribed by a doctor.

But lactulose is not suitable for everyone. For example, it may not be suitable if:

• you've had an allergic reaction or serious side effect from lactulose or a similar medicine before
• you're lactose intolerant, allergic to the sugars galactose or fructose, or have a rare condition called galactosaemia
• you have a bowel condition such as irritable bowel syndrome, diverticular disease or Crohn's disease, or a blockage in your bowel that is not from constipation
• you have diabetes and are taking lactulose for hepatic encephalopathy – high doses of lactulose can affect your blood sugar (glucose) levels

Check the packet or leaflet that comes with your medicine to see if it's suitable for you or your child. Speak to a pharmacist or doctor if you're not sure if you can take it.

Breastfeeding and lactulose

You can take lactulose while breastfeeding.

It's rare for breastfed babies to get any side effects from medicine you're taking, but speak to a healthcare professional if you have any concerns about your baby.

Pregnancy and lactulose

You can take lactulose if you're pregnant, but it's best to speak to a pharmacist or doctor first.

Find out more about taking lactulose during pregnancy on the Bumps (Best Use of Medicines in Pregnancy) website

Taking lactulose with other medicines, food and drink

There are some medicines, remedies and supplements that may not mix well with lactulose.

Before you take lactulose, check the packet or leaflet that comes with the medicine to see if it's suitable for you. Speak to a pharmacist or doctor if you're not sure if you can take it.

Food, drink and alcohol with lactulose

You can eat and drink as normal while taking lactulose.

It's important to drink plenty of fluid when taking lactulose to avoid dehydration.