Imodium A-D vs. Pepto-Bismol

Medically reviewed by Zara Risoldi Cochrane, PharmD, MS, FASCP on August 23, 2016Written by University of Illinois-Chicago, Drug Information Group on August 23, 2016

Introduction

Nobody likes to talk about diarrhea, so let us save you a few extra questions when it comes to finding the right treatment. In this comparison, you can find important information about Imodium A-D and Pepto-Bismol, including what makes them different.

Imodium A-D vs. Pepto-Bismol

Imodium A-D and Pepto-Bismol are both available over the counter without a prescription. They treat diarrhea, but they don’t work in exactly the same way. Also, Pepto-Bismol can treat other symptoms.

The tables below compare certain features of each drug.

Active ingredientImodium A-DPepto-Bismol
loperamide hydrochlorideX
bismuth subsalicylate X
Symptom(s) treatedImodium A-DPepto-Bismol
diarrheaXX
upset stomach X
heartburn X
nausea X
indigestion X
Forms and strengthsImodium A-DPepto-Bismol
oral capsule2 mgnot available
oral caplet2 mg262 mg
chewable tablet2 mg262 mg
oral liquid1 mg/5 mL, 1 mg/7.5 mL262 mg/15 mL, 525 mg/15 mL

How they work

Both drugs decrease the flow of fluids and electrolytes into your bowels. The rest of their drug action differs, however. Imodium A-D slows the movement of fluids through your intestine and reduces the frequency and volume of your stools. Pepto-Bismol, on the other hand, reduces inflammation of your intestines and kills bacteria that cause diarrhea.

Dosage

An important difference between Imodium A-D and Pepto-Bismol is that Imodium A-D can be used in children younger than 12 years. If you’re looking for medication specifically for your kids, this may be an important distinction.

If you’re using Imodium A-D for traveler’s diarrhea, do not take more than 8 mg per day for two days unless your doctor says it’s safe for you.

Side effects and warnings

If you take these drugs at the recommended dosage, side effects are not likely. Most people can take Imodium A-D or Pepto-Bismol and have few or no side effects. When people do have side effects, it’s often because they took more than they should.

If you have side effects, you might not be able to tell if they’re from the drug or from your diarrhea. This is because the more common side effects of both drugs include:

  • dizziness
  • constipation
  • headache
  • stomach pain
  • drowsiness
  • nausea
  • vomiting

With Imodium A-D, you may also have dry mouth or a feeling of fullness. With Pepto-Bismol, you may also have stool discoloration and darkening of your tongue. This discoloration is not harmful.

Learn more: Why Pepto-Bismol can give you a black tongue »

Serious side effects

Serious side effects of Imodium A-D may include a severe allergic reaction with symptoms that include:

  • rash
  • difficulty breathing
  • skin blisters or peeling

A serious side effect of Pepto-Bismol may include ringing in your ears. This effect can be a sign that you’ve taken too much of the drug.

Interactions

Taking certain drugs together can cause an interaction. Interactions can make one or more of the drugs involved less effective. They can also increase your risk of side effects.

Because of this, you shouldn’t take Imodium A-D and Pepto-Bismol together. Taking them together won’t increase how well they work for you. Instead, doing so can increase your risk of side effects. This is because their side effects are the same.

If you take other drugs, talk to your doctor before taking Imodium A-D or Pepto-Bismol. The table below lists examples of drugs that can interact with Imodium or Pepto-Bismol.

Imodium A-D interacting drugsPepto-Bismol interacting drugs
drugs for fungal infectionsdiabetic medications
drugs for psychiatric disordersmethotrexate
antibioticsaspirin
drugs for cholesterolgout medications
metoclopramideblood thinners (anticoagulants)
angiotensin-converting enzyme (ACE) inhibitors
Ibuprofen
naproxen

Other conditions

One of these drugs may not be right for you if you have a specific medical condition. The following table lists examples of the conditions that each drug may affect.

Imodium A-DPepto-Bismol
acute dysenteryactive bleeding ulcer
intestinal bacterial infectionbleeding disorder
ulcerative colitiskidney disease
liver disease gout
diabetes

Contact your doctor if you have one of these conditions to see if Imodium A-D or Pepto-Bismol is better for you. Your doctor may also suggest a different drug entirely.

Pharmacist’s advice

All in all, Imodium A-D and Pepto-Bismol are both safe and effective over-the-counter treatments for diarrhea in most people. A few notable differences may affect which drug you choose. For example:

  • Pepto-Bismol can treat several other related symptoms, such as heartburn, nausea, and indigestion. Imodium A-D only treats diarrhea.
  • Imodium can be used in children as young as 2 years, but Pepto-Bismol should only be used in people who are 12 years or older.
  • The active ingredient in Pepto-Bismol may turn your tongue or stools black. This effect is harmless, but it may bother you anyway.

If you find that one of these drugs is right for you, remember to use it exactly as recommended. Don’t use either drug for more than two days. If your symptoms don’t improve after two days or if they get worse, contact your doctor.

CMS Id: 109504