Loperamide: a medicine used to treat diarrhoea (2023)

1. About loperamide

Loperamide is a medicine to treat diarrhoea (runny poo). It can help with short-term diarrhoea or irritable bowel syndrome (IBS).

Loperamide is also used for recurring or longer lasting diarrhoea from bowel conditions such as Crohn's disease, ulcerative colitis and short bowel syndrome.

If you have a colostomy (an opening in your stomach to collect poo from your body), loperamide can make your poo thicker. It does this by slowing down your food as it passes through your gut.

You can buy loperamide from pharmacies and supermarkets. It is also available on prescription for treating some bowel conditions.

It comes as tablets, including tablets that melt on your tongue, capsules and a liquid. The liquid is only available on prescription. The tablets that melt are called Imodium Instants or Imodium Instant Melts

Loperamide is also available combined with simeticone. Simeticone is used to treat farting (flatulence or wind). Taking these medicines together helps if you have diarrhoea with painful stomach cramps and bloating.

Loperamide mixed with simeticone is known by the brand names Imodium Plus Caplets and Imodium Plus Comfort Tablets.

2. Key facts

  • Diarrhoea that starts suddenly usually gets better on its own within 5 to 7 days. If you need immediate short-term relief, taking loperamide can reduce the number of times you go to the toilet and it makes your poo less watery.
  • Do not give loperamide to children under 12 years old unless their doctor has prescribed it.
  • If you've bought loperamide from a pharmacy or shop, do not take it for more than 48 hours without talking to a doctor.
  • Only take the recommended amount. Too much loperamide can cause serious heart problems (including a fast or irregular heartbeat).
  • Pharmacies and supermarkets may sell their own brands of loperamide, usually called anti-diarrhoea or diarrhoea relief capsules.
  • Some products have IBS in the name. However, they're no different from others. If you have IBS you can also use brands without IBS in the name.

3. Who can and cannot take loperamide

You can buy loperamide from pharmacies and supermarkets or you can get it on prescription.

Loperamide is available to buy without a prescription for:

  • anyone aged 12 and older with short-term diarrhoea
  • an adult (18 years and older) with IBS diarrhoea, but only if a doctor has diagnosed IBS. If you are not sure whether you have IBS, talk to your doctor

It's available on prescription only for:

  • children again 11 years and younger
  • young people aged 12 to 17 years with IBS or long-lasting diarrhoea
  • adults with long-lasting diarrhoea

Important: Younger children

Only give loperamide to children aged 11 years or under if their doctor prescribes it.

Loperamide is not suitable for some people.

Do not take loperamide if you:

  • have severe diarrhoea after taking antibiotics
  • are having a flare-up of an inflammatory bowel condition like ulcerative colitis
  • are constipated or your stomach looks swollen

Check with your doctor before taking loperamide if you:

  • have had an allergic reaction to loperamide or any other medicines in the past
  • have had diarrhoea for more than 48 hours
  • have HIV and your stomach becomes swollen
  • have liver problems
  • have blood in your poo and a high temperature – these can be signs of dysentery
  • are trying to get pregnant, are already pregnant or you're breastfeeding

If you have diarrhoea and IBS, talk to your doctor before taking loperamide if you:

  • are aged 40 years or over and it's some time since your last IBS attack, or if your symptoms are different this time
  • have recently had blood in your poo (your poo might be bright red or black)
  • get bad constipation
  • are feeling or being sick
  • have lost your appetite or lost weight
  • a high temperature
  • have trouble peeing or find peeing painful
  • have recently travelled abroad – you may have picked up a stomach bug

4. How and when to take loperamide

If you've bought loperamide from a pharmacy or shop, follow the instructions that come with the packet.

If your doctor has prescribed loperamide for you or your child, follow their instructions about how and when to take it.

How to take it

You can take loperamide with or without food.

Capsules and tablets: swallow these whole, with a drink of water.

Tablets that melt in your mouth: put the tablet on your tongue and let it melt in your saliva. You can then swallow it without a drink. Do not chew it.

Liquid: this comes with a measuring cup, plastic syringe or spoon to help you measure the right dose. If you do not have one, ask your pharmacist. Do not use a kitchen teaspoon as it will not give the right amount of medicine.

Dosage and strength

Loperamide comes as:

  • tablets and capsules that contain 2mg of loperamide
  • liquid that contains 1mg of loperamide in a 5ml spoonful

The recommended dose depends on the type of diarrhoea you have and your age.

Adults (over 18), with short-term diarrhoea or IBS

The usual starting dose is:

  • capsules or tablets: take 2 capsules or tablets, taken immediately. Then take 1 capsule or tablet after each runny poo.
  • liquid: four 5ml spoonfuls, taken immediately. Then take 2 spoonfuls after each runny poo.

Stop taking loperamide as soon as your symptoms settle down.

The recommended maximum dose in 24 hours is:

  • 6 capsules or tablets, if you buy loperamide from a shop
  • 8 capsules or tablets, or 16 spoonfuls of liquid (5ml each), if you have a prescription or buy loperamide from a pharmacy

Do not take loperamide for more than 48 hours without talking to a doctor.

Adults (over 18) with long-lasting or recurring diarrhoea

Most cases of diarrhoea get better in 5 to 7 days. If your diarrhoea does not stop in 7 days, talk to your doctor. It is important to understand the causes and to treat any complications, for instance dehydration.

If your doctor prescribes loperamide for long-lasting diarrhoea, they will tell you how much to take. The usual starting dose is:

  • 2 to 4 capsules or tablets, spaced evenly throughout the day
  • 4 to 8 spoonfuls of liquid loperamide (5ml each), spaced evenly throughout the day

Your doctor will adjust your dose according to your symptoms and how well loperamide is working, up to a maximum of:

  • 8 tablets or capsules in 24 hours
  • 16 spoonfuls of liquid loperamide (5ml each) in 24 hours

Once you're on the right dose, your doctor will usually recommend dividing your daily dose, so you take half in the morning and half in the afternoon or evening.

Occasionally patients with a colostomy (stoma) need a higher dose. Only take a higher dose if your doctor tells you to.

Children's doses

Do not give loperamide to children under 12 years old unless their doctor prescribes it.

  • Age 12 years and over with short-term diarrhoea – the dose is the same as for adults.
  • Age 12 to 17 years with IBS or long-lasting diarrhoea – follow the instructions from their doctor. This is given on prescription only.
  • Age 11 years or younger – follow the instructions from their doctor.

If a doctor prescribes loperamide for your child, they will use their weight or age to work out the right dose. The dose also depends on their symptoms.

What if I forget to take it?

If you miss a dose of loperamide, do not worry. Just take a dose after you next go to the toilet and have a runny poo.

Do not take a double dose to make up for the one you forgot.

What if I take too much?

Do not take more than the recommended amount.

If you take 1 extra dose of loperamide as a one-off, it's unlikely to harm you. But taking higher doses can cause serious heart problems. The signs include having a fast or irregular heartbeat.

Urgent advice: Contact 111 for advice now if:

  • you take 2 extra doses of loperamide or more
  • you take more than the recommended dose and get a fast or irregular heartbeat

Go to 111.nhs.uk or call 111

If you need advice for a child under the age of 5 years, call 111.

5. Side effects

Like all medicines, loperamide can cause side effects, but many people have no side effects or only minor ones.

Common side effects

These common side effects happen in more than 1 in 100 people.

Talk to your doctor or pharmacist if these side effects bother you or do not go away:

  • constipation (difficulty doing a poo)
  • feeling dizzy
  • feeling sick
  • headaches
  • farting (wind)

Serious side effects

It's rare to have a serious side effect with loperamide.

Tell a doctor straight away if you:

  • feel faint or less alert, or if you pass out (faint)
  • start moving in a clumsy, uncoordinated way

Serious allergic reaction

In rare cases, it's possible to have a serious allergic reaction (anaphylaxis) to loperamide.

Immediate action required: Call 999 or go to A&E now if:
  • you get a skin rash that may include itchy, red, swollen, blistered or peeling skin
  • you're wheezing
  • you get tightness in the chest or throat
  • you have trouble breathing or talking
  • your mouth, face, lips, tongue or throat start swelling

You could be having a serious allergic reaction and may need immediate treatment in hospital.

These are not all the side effects of loperamide. For a full list, see the leaflet inside your medicines packet.


You can report any suspected side effect using the Yellow Card safety scheme.

Visit Yellow Card for further information.

6. How to cope with side effects of loperamide

What to do about:

  • constipation – stop taking loperamide. If you have constipation, eat more fibre by having fresh fruit, vegetables and cereals, and drink plenty of water. Try to exercise regularly, for example by going for a daily walk or run. If this does not help, talk to your pharmacist or doctor.
  • feeling dizzy – if loperamide makes you feel dizzy when you stand up, try getting up very slowly or stay sitting down until you feel better. If you begin to feel dizzy, lie down so that you do not faint, then sit until you feel better. Avoid driving, cycling, or using tools or machines if you feel dizzy.
  • feeling sick – try taking loperamide with or after a meal or snack. It may also help if you stick to simple meals and avoid rich or spicy food.
  • headaches – make sure you rest and drink plenty of fluids. Do not drink too much alcohol. Ask your pharmacist to recommend a painkiller. Talk to your doctor if the headaches last longer than a week or are severe.
  • farting (wind) – avoid foods that cause wind like lentils, beans and onions. It might also help to eat smaller and more frequent meals, eat and drink slowly, and exercise regularly. There are products you can buy from a pharmacy to help with wind. Loperamide can be bought mixed with simeticone, a medicine for wind.

7. Pregnancy and breastfeeding

Loperamide in pregnancy

Loperamide is not usually recommended in pregnancy. This is because there is not enough information to say whether it is safe or not.

If you're pregnant, talk to your doctor before taking loperamide.

They'll be able to advise you about the benefits and possible harms of taking it. This will depend on how many weeks pregnant you are and why you need to take it.

If you’re trying to get pregnant, talk to your doctor if you take loperamide on prescription as part of ongoing treatment for a bowel condition.

Loperamide and breastfeeding

It is OK to take loperamide for a couple of days while you're breastfeeding. Hardly any loperamide passes into breast milk, and so it will not affect your baby.

If you notice that your baby isn’t feeding as well as usual, seems unusually sleepy, or if you have any other concerns about your baby, then talk to your doctor, midwife or health visitor.

Non-urgent advice: Tell your doctor if you're:

  • trying to get pregnant
  • pregnant
  • breastfeeding

For more information about how taking this medicine can affect you and your baby, read this leaflet about loperamide on the Best Use of Medicines in Pregnancy (BUMPs) website.

8. Cautions with other medicines

There are some medicines that can affect the way loperamide works.

Check with a pharmacist or doctor if you're taking:

  • ritonavir, used to treat HIV infection
  • quinidine, used to treat abnormal heartbeats or malaria
  • itraconazole, used to treat fungal infections
  • gemfibrozil, used to treat high cholesterol
  • desmopressin, used for bedwetting or peeing too much
  • other medicines for diarrhoea, constipation, or any other stomach and bowel problems

Speak to your doctor if your diarrhoea is very severe and you take metformin for diabetes, or medicines for high blood pressure or heart failure. Your doctor may tell you to stop taking these medicines for a few days until your diarrhoea is better.

Mixing loperamide with herbal remedies or supplements

There's very little information about taking herbal remedies and supplements with loperamide.

Important: Medicine safety

Tell your doctor or pharmacist if you're taking any other medicines, including herbal medicines, vitamins or supplements.

9. Common questions about loperamide

How does loperamide work?

Loperamide is an anti-motility medicine. This means that it slows down food as it goes through your gut. Your body can then draw in more water from your intestines, so that your poos get firmer and you poo less often.

How long does loperamide take to work?

Loperamide usually starts to work within 1 hour to make your diarrhoea better.

How long will I take it for?

Most people only need to take loperamide for 1 to 2 days.

You may need to take it for longer if your diarrhoea is because of a bowel condition such as Crohn's disease, ulcerative colitis or short bowel syndrome.

If you've bought loperamide from a shop or pharmacy, do not take it for more than 48 hours without talking to a doctor.

Why is it important not to take loperamide for longer than recommended?

If you've bought loperamide from a shop or pharmacy, do not take it for more than 48 hours without talking to a doctor.

Although diarrhoea is usually nothing to worry about, it can sometimes lead to dehydration. This can be serious if you do not get the correct treatment.

Diarrhoea can also sometimes be a warning sign of another problem. For this reason, it's important to see a doctor to find out the cause of your diarrhoea if it continues beyond 7 days.

Is it safe to take for a long time?

If you've bought loperamide for short-term diarrhoea, do not take it for longer than 48 hours without talking to a doctor.

Loperamide may be used for long-lasting diarrhoea and by people who have a colostomy (stoma) if their doctor prescribes it.

Can I take loperamide to prevent diarrhoea?

Do not take loperamide to prevent diarrhoea, unless your doctor tells you to.

It's not been officially approved and tested for preventing diarrhoea.

Can I drink alcohol with it?

It's best not to drink alcohol while you're taking loperamide. Alcohol makes you more likely to have side effects such as feeling sleepy or dizzy and having difficulty concentrating.

Is there any food or drink I need to avoid?

Apart from avoiding alcohol, you can eat and drink normally while you're taking loperamide. However, if you have diarrhoea it's best to avoid fatty or spicy food.

Can I drive or ride a bike?

Loperamide can make you feel dizzy, tired or sleepy. You might also feel less alert, feel faint or pass out. If this happens to you do not drive, cycle or use machinery or tools until the effect has worn off.

Can I take loperamide with painkillers?

Yes, you can take loperamide at the same time as everyday painkillers like paracetamol and ibuprofen.

Are there any other treatments that could help diarrhoea?

There is another medicine for diarrhoea called co-phenotrope. This works in a similar way to loperamide to slow down your gut.

You do not usually need an antibiotic for diarrhoea. However, occasionally your doctor will prescribe an antibiotic if you have severe diarrhoea caused by a specific kind of bacteria.

Speak to a pharmacist if you have signs of dehydration, such as peeing less than usual or having dark, strong-smelling pee. Your pharmacist can recommend oral rehydration sachets. These are powders that you mix with water and then drink.

If you've been diagnosed with a particular health problem that's causing your diarrhoea, treating the problem may help improve your symptoms. For example, you can help relieve IBS with changes to your diet and medicines.

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