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How IMODIUM® Works

How IMODIUM® (Loperamide) Products Work: Dosage, Side Effects, Ingredients

IMODIUM® was developed by Dr. Janssen and launched in 1973. Dr. Janssen was the first man to deliver the values that IMODIUM® is known for today: delivering effective relief to ease the uncomfortable disruptions for people suffering from diarrhea. And we’ve been doing just that for over 40 years globally.

Choosing the diarrhea treatment that’s right for you means first understanding how it works inside your body.

What Is IMODIUM® And How Does It Work?

IMODIUM® is an effective over-the-counter relief option for diarrheal symptoms, but choosing the diarrhea treatment that’s right for you means first understanding what is going on inside of your body.

What Happens In Your Digestive System When You Get Diarrhea?

When your digestive system is in its normal rhythm, food and fluids pass from the stomach into the small intestine. Food is broken down and nutrients are absorbed along with most of the fluid. The remaining waste and some water pass into the colon (large intestine) where more water is absorbed. Finally, the waste is passed in the form of solid stools.

When the cells in your small intestine or colon are irritated by bacteria, viruses, or inflammation, your intestines may become overactive. This causes fluids and nutrients to pass through the colon too quickly, which means that less fluid gets absorbed by the body. The result is loose or watery stools, commonly known as diarrhea1 .

Loperamide Hydrochloride Mechanism Of Action

IMODIUM® products contain an active ingredient called loperamide hydrochloride, which works to slow the movement of your intestines. Loperamide binds to a molecule (receptor) in the gut wall2. When loperamide binds this receptor, this causes the gut to contract less and slows down the time it takes for fluids and food to move through the intestines. This allows the body to start absorbing fluids and salts as it should, restoring stools back to a more normal consistency.

IMODIUM® For Diarrhea

There are different IMODIUM® products available to choose from to help treat your symptoms. For example, you may have gas, cramps or bloating accompanying your diarrhea symptoms. IMODIUM® products come in a variety of convenient sizes and forms.

Figure out which IMODIUM® product is best for you

Use only as directed
Front package of IMODIUM® Anti-Diarrheal Medicine Fast-Acting Loperamide Caplets.
IMODIUM® A-D Anti-Diarrheal Medicine Softgels.
IMODIUM® Multi-Symptom Anti-Diarrheal Relief Medicine Caplets.
IMODIUM® Anti-Diarrheal Oral Solution Liquid Medicine.
IMODIUM® Anti-Diarrheal Liquid Oral Solution, Diarrhea Medicine for Kids.
Form and Flavor
Liquid Gels
Liquid, Mint Flavor
Liquid, Mint Flavor
Available In
6ct, 12ct, 24ct
12ct, 24ct
12ct, 18ct, 24ct
4oz, 8oz
Active Ingredient(s)
Loperamide HCl 2 mg
Loperamide HCl 2 mg
Loperamide HCl 2 mg; Simethicone 125 mg
Loperamide HCl 1 mg
(in each 7.5 ml)
Loperamide HCl 1 mg
(in each 7.5 ml)
Relieves Diarrhea
Relieves Cramps and Pressure
Relieves Gas
Relieves Bloating

IMODIUM® (Loperamide) Side Effects, Warnings, And Interactions

If you are using the over-the-counter product to self-treat your diarrhea, read all the directions on the product package.

What Are Loperamide (IMODIUM®) Side Effects?

Over the counter loperamide (IMODIUM®) products have few undesired effects when they are used as directed on the product label. If constipation occurs, stop using IMODIUM® and contact your doctor if the effect is severe. Nausea, vomiting, flatulence or dry mouth may occur, but these also may be due to the diarrhea (or illness causing the diarrhea)3.

When using this product tiredness, drowsiness or dizziness may occur. Be careful when driving or operating machinery. If any of these effects persist or worsen, contact your doctor promptly.

Serious side effects to loperamide are rare. Get medical help immediately if you notice symptoms of a serious allergic reaction, including a rash, itching or swelling, rapid or irregular heartbeat, severe dizziness or trouble breathing3.

What Drugs Interact With Loperamide (IMODIUM®)?

Drug interactions may change how your medications work or increase your risk for serious side effects. Ask a doctor or pharmacist before use if you are taking other drugs including herbal medicines. Loperamide may interact with certain drugs and herbal supplements3,4. Be sure to let your doctor or pharmacist know if you are taking the following medications3:

  1. Drugs that slow down the action of the stomach and intestines (for example, some antidepressants and cold and allergy medication), because these can make the effect of IMODIUM® too strong.
  2. Sedating medications.
  3. Ritonavir – treats HIV/AIDS.
  4. Quinidine – treats irregular heartbeats and also malaria.
  5. Oral desmopressin – relieves excessive urination.
  6. Itraconazole or ketoconazole – antifungal medication.
  7. Gemfibrozil – a cholesterol medication.

When May Loperamide (IMODIUM®) Not Be Right For You?

In some cases, IMODIUM® may not be the best medication to control or treat your diarrhea.

Do not use if you have bloody or black stool. Ask a doctor before use if you have fever, mucus in the stool, a history of liver disease or history of abnormal heart rhythm.

Will IMODIUM® Make It Hard For Me To Poop?

IMODIUM® slows down the movement (contractions) in your intestine so that you pass firmer stools less often. But usually, the drug doesn’t completely stop you from having bowel movements3.

Constipation may occur. If so, stop taking IMODIUM® and consult your doctor if constipation is severe. Make sure that you drink plenty of water, since proper hydration helps reduce constipation.

Who Can Use IMODIUM® Products To Treat Diarrhea?

People of all ages can get diarrhea. In the United States, acute diarrhea is one of the most commonly reported illnesses. IMODIUM® is suitable for adults and children over 6 years of age.


IMODIUM® A-D Diarrhea Medicine For Children is suitable for children 6 years of age and older.

Children with diarrhea can become dehydrated – even more quickly than adults can – so it’s a good idea to keep children hydrated. An oral rehydration treatment may help.

Oral rehydration solutions replace lost fluids and salts and help prevent dehydration. Here are some helpful tips for managing your child’s diarrhea:

  1. Avoid sweetened fluids like soft drinks, energy drinks, sugar water, and undiluted fruit juices. These all contain sugar, which can worsen diarrhea symptoms.
  2. As symptoms improve, giving your child soft, bland foods – such as bread, rice, yogurt, and bananas – can help restore the natural rhythm of the gut.

If your child’s diarrhea lasts longer than 48 hours, or gets worse, or you’re otherwise concerned about his or her health, consult your healthcare professional.

IMODIUM® During Pregnancy Or Breastfeeding

As with many medicines, IMODIUM® products are not recommended when you’re pregnant or breastfeeding.

If pregnant or breastfeeding, ask your healthcare professional for advice on how to treat your diarrhea.

IMODIUM® (Loperamide) Dosage For Adults And Kids

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