Loperamide

What is loperamide?

Loperamide is a medicine used to treat diarrhoea. It is commonly known by the brand name Imodium and is available both over the counter and by prescription[1]. 

What Is loperamide used for?

It is used for[1]: 

• Short-term diarrhoea  

• Diarrhoea related to Irritable Bowel Syndrome (IBS) 

• Chronic diarrhoea due to conditions like: 

• Crohn’s disease 

• Ulcerative colitis 

• Short bowel syndrome 

• Managing bowel output in people with an ileostomy or colostomy 

How does loperamide work?

Loperamide works by slowing down the movement of the gut. This gives the intestines more time to absorb water and electrolytes, which helps firm up stools and reduce the frequency of bowel movements. For people with a colostomy, it can help make poo thicker and reduce the flow[1]. 

Who can take loperamide?

Loperamide is generally suitable for adults and children over 12 years (for short-term diarrhoea). It should not be taken by[1]: 

• Children under 12 unless prescribed 

• People with: 

• Severe diarrhoea after antibiotics 

• Bloody, mucousy or severe diarrhoea or dysentery 

• Fever or feel systemically unwell 

• Inflammatory bowel disease during a flare-up 

• A bowel blockage or ongoing constipation 

• Certain bacterial infections (e.g. salmonella, shigella) 

You should talk to your doctor before taking loperamide if you[1]: 

• Have ever had an allergic reaction to loperamide 

• Have had diarrhoea for more than 48 hours 

• Have HIV and your stomach is swollen 

• Have liver problems 

• Have blood in your poo and a high temperature 

• Are pregnant, trying to get pregnant, or breastfeeding 

If you have diarhoea and IBS, you should talk to your doctor before taking loperamide if you[1]: 

• Are 40 or over, and it’s been a little while since your last IBS attack or you’re experiencing different symptoms 

• Have had blood in your poo recently 

• Have trouble or pain when peeing 

• Get bad constipation 

• Are nauseous or are being sick 

• Have recently been abroad 

• Have lost your appetite or weight 

• Have a high temperature 

Please tell your doctor or pharmacist about any conditions you may have or medication you take before you start treatment, and always follow the instructions in the Patient Information Leaflet[2].  

What is the typical dosage of loperamide?

If you have bought loperamide in a shop, you should follow the instructions in the Patient Information Leaflet. If you have been prescribed loperamide for you or your child, follow the doctor or pharmacist’s instructions about how and when to take it[1]. 

Loperamide comes as 2mg tablets, capsules and orodispersable tablets[1]. 

For adults with short-term diarrhoea or IBS, the usual starting dose is 2 capsules or tablets taken immediately. Then a single tablet or capsule after each loose stool. You should stop taking loperamide once your symptoms settle down. Don’t take more than 6 tablets or capsules if bought from a shop, or 8 if prescribed by a doctor or pharmacist. Don’t take loperamide for more than 48 hours without consulting a doctor or pharmacist first[1]. 

For adults with long-lasting or recurring diarrhoea, most cases will improve in 5 to 7 days. If it doesn’t, you should speak to your doctor who can advise and treat any underlying complications. Your doctor may prescribe loperamide for long-lasting diarrhoea, usually 2 to 4 capsules or tablets, spaced evenly throughout the day. Once on the correct dose, your doctor will usually recommend dividing your daily dose, so you take a half in the morning, and the other half in the afternoon or evening[1]. 

How do you take loperamide?

Loperamide comes as 2mg tablets, capsules (both swallowed whole with water) and orodispersable tablets (dissolved on the tongue without water, do not chew it)[1]. 

It can be taken with or without food. Always follow the instructions on the label or your doctor’s advice. 

Can you stop taking loperamide?

Yes, you can stop taking it once your diarrhoea improves. Loperamide is not addictive and is not intended for long-term use unless prescribed for a chronic condition Loperamide comes as 2mg tablets, capsules and orodispersable tablets[1]. 

What do you do if you think you’ve taken too much loperamide?

Taking one extra dose of loperamide is unlikely to cause harm, but exceeding that can cause serious side effects, including[1]: 

• Irregular heartbeat 

• Fainting 

• Unresponsiveness 

If you suspect an overdose, especially if 2 or more extra doses have been taken, call 999 or go to A&E immediately. Take the medicine packaging with you. 

What do I do if I miss my dose of loperamide?

If you’re taking loperamide regularly (for chronic diarrhoea)[1]: 

• Take the missed dose as soon as you remember 

• If it’s nearly time for your next dose, skip the missed one 

• Do not take two doses at once 

Medicines you can and can’t take with loperamide

You should avoid taking loperamide with[1]: 

• Other anti-diarrhoeal, constipation or stomach medicines (may increase risk of side effects) 

• Quinidine (used for heart rhythm problems) 

• Ritonavir (HIV treatment) 

• Clozapine (mental health medication) 

• Itraconazole or ketoconazole (antifungals) 

• Desmopressin (bedwetting or excessive peeing medication) 

• Gemfibrozil (cholesterol medication) 

• Metformin (diabetes medication) 

• Medication for high blood pressure or heart failure 

But you can take loperamide with, amongst others: 

• Oral rehydration salts 

• Most over-the-counter painkillers like paracetamol 

Always inform your doctor or pharmacist about all medications and supplements you take before you start a new medicine, and follow the instructions in the Patient Information Leaflet[2].  

What are the side effects of loperamide?

The most common side effects include[1]: 

• Constipation 

• Headaches 

• Nausea 

• Flatulence  

Serious but rare side effects include[1]: 

• Severe abdominal pain or swelling 

• Irregular heartbeat 

• Feeling faint 

• Clumsiness or lack of coordination 

• Severe constipation 

• Difficulties peeing 

You should contact your GP if you experience any of these symptoms. In rare cases, the medicine may cause a serious allergic reaction (anaphylaxis). You should call 999 or visit A&E immediately if you believe this is happening[1]. 

Symptoms of anaphylaxis include: 

• Difficulty breathing 

• Tightness in throat and chest 

• Swelling of the tongue or throat 

• Feeling faint or dizzy 

• Blue/grey skin or lips 

• Loss of consciousness 

If you experience any side effects, including those not listed, you are encouraged to report them via the Yellow Card Scheme or contact your doctor, pharmacist, or nurse. This information is intended as a summary for general awareness and does not replace professional medical advice. 

The information provided in the side effects section is not a comprehensive list of all possible side effects associated with this medication. For a complete list of side effects, please refer to the Patient Information Leaflet (PIL) provided with your medication or consult your healthcare professional[2]. 

Frequently asked questions about loperamide

Can I drink alcohol with loperamide? 

It’s best to avoid alcohol, as it may increase side effects like drowsiness and dizziness[1]. 

Can I drive while taking loperamide? 

Yes, but avoid driving if you feel dizzy or drowsy after taking it[1]. 

Is it addictive? 

Loperamide is not addictive at recommended doses. However, misuse (e.g., in very high doses) can be dangerous and lead to serious health problems[1]. 

Can I take loperamide during pregnancy or breastfeeding? 

Only take loperamide if advised by a doctor. It’s usually not recommended during the first trimester or while breastfeeding[1]. 

For the official NHS guide to loperamide, visit their website.