Imodium: Helpful Information to Know

Medically reviewed by Darren Hein, PharmD on July 11, 2016Written by University of Illinois-Chicago, Drug Information Group on July 11, 2016

Introduction

We’ve all been there. Whether from a stomach bug or an exotic morsel we sampled in Morocco, we’ve all had diarrhea. And we’ve all wanted to fix it. That’s where Imodium can help.

Imodium is an over-the-counter (OTC) medication that’s used to relieve diarrhea or traveler’s diarrhea. The following information can help you decide if Imodium is a good choice to help you feel better.

About Imodium

Normally, the muscles in your intestines contract and release at a certain speed. This helps move food and fluids through your digestive system. During this process, the intestines absorb water and nutrients from the food you eat.

But with diarrhea, the muscles contract too quickly. This moves food through your system too fast. Your intestines don’t absorb the normal amounts of nutrients and fluids. This causes watery bowel movements that are larger and more frequent than normal. It also increases the amount of fluids and electrolytes that your body loses. Electrolytes are salts the body needs to function well. Having very low levels of fluids and electrolytes can be dangerous. This condition is called dehydration.

The active ingredient in Imodium is the drug loperamide. It works by making the muscles in your intestines contract more slowly. This in turn slows the movement of food and fluids through your digestive tract, which allows the bowel to absorb more fluids and nutrients. The process makes your bowel movements smaller, more solid, and less frequent. It also decreases the amount of fluids and electrolytes your body loses.

Forms and dosage

Imodium is available as a caplet and a liquid. Both forms are taken by mouth. These forms should be used for no more than two days. However, the caplet is also available in a prescription form that may be used long-term. The prescription-strength form is used to treat diarrhea caused by digestive diseases such as inflammatory bowel disease.

The recommended dosage for Imodium is based on age or weight.

Adults and children 12 years or older

The recommended dosage is 4 mg to start, followed by 2 mg for each loose stool that occurs after that. Don’t take more than 8 mg per day.

Children younger than 12 years

Dosage should be based on weight. If the child’s weight is not known, dosage should be based on age. When using either weight or age, use the following information:

  • Children 60-95 pounds (ages 9-11 years): 2 mg to start, then 1 mg after each loose stool that occurs after that. Don’t take more than 6 mg per day.
  • Children 48-59 pounds (ages 6-8 years): 2 mg to start, then 1 mg after each loose stool that occurs after that. Don’t take more than 4 mg per day.
  • Children 29-47 pounds (ages 2-5 years): Use Imodium only by the advice of your child’s doctor.
  • Children under 2 years: Do not give Imodium to children younger than 2 years of age.

Side effects

Imodium is generally well-tolerated by many people. However, it can sometimes cause some side effects.

More common side effects

The more common side effects of Imodium can include:

  • constipation
  • dizziness
  • tiredness
  • headache
  • nausea
  • vomiting
  • dry mouth

Serious side effects

Serious side effects of Imodium are rare. Call your doctor right away if you have any of the following:

  • Severe allergic reaction, with symptoms such as:
    • severe rash
    • trouble breathing
    • swelling of the face or arms
  • Paralytic ileus (inability of the intestine to move waste out of the body. This typically occurs in cases of overdose or in children under the age of 2 years). Symptoms can include:
    • swelling of the abdomen
    • pain in the abdomen

Drug interactions

Imodium interacts with certain drugs that break down in the body in the same way. The interactions can lead to increased levels of either medication in your body. Imodium also interacts with other anti-diarrheal drugs or medications that cause constipation.

Some examples of medications that can interact with Imodium include:

Warnings

Imodium is a safe medication for most people. However, it should be used carefully. And in some cases, it should be avoided. The following warnings can help keep you safe.

Conditions of concern

Talk with your doctor before taking Imodium if you have any of the following conditions:

  • liver problems
  • AIDS with infectious colitis
  • ulcerative colitis
  • an intestinal bacterial infection
  • allergy to Imodium

Other warnings

Do not take more than the maximum daily dosage of Imodium. Also, do not take it longer than two days unless directed by your doctor to do so. You should see an improvement in your symptoms within two days. If you don’t, call your doctor. Your diarrhea may be caused by bacteria, a virus, or another cause. This may require treatment with a different medication.

Don’t take Imodium if you have blood in your stools or black stools. These symptoms likely mean there is a problem in your stomach or intestines. You should see your doctor.

Never take Imodium if you have abdominal pain without diarrhea. Imodium is not approved to treat abdominal pain without diarrhea. Depending on the cause of your pain, taking Imodium could make the pain worse.

In case of overdose

To avoid overdose, be sure to carefully follow the dosage instructions on your Imodium package. Symptoms of an overdose of Imodium can include:

  • nausea
  • vomiting
  • severe drowsiness
  • pain in your abdomen
  • severe constipation

Pregnancy and breastfeeding

Not enough research has been done to know if Imodium is safe to use in pregnant women. Therefore, talk with your doctor before taking Imodium. Ask if this medication is safe for you to use during pregnancy.

If you’re breastfeeding, you should also ask your doctor if Imodium is safe for you. It’s known that small amounts of Imodium may pass into breast milk. Research indicates that it’s not likely to harm a child who is breastfed. However, you should still consult your doctor before using Imodium.

Learn more: Pregnancy and diarrhea: Causes and remedies »

Talk with your doctor

If you have questions about Imodium, talk with your doctor or pharmacist. Also call your doctor if your symptoms get worse or your diarrhea lasts longer than two days.

A range of OTC medications can help treat diarrhea. The information above can help you decide if Imodium is a good choice for you.

Read more: The six most effective diarrhea remedies »

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