Antidiarrheal Medicines: OTC Relief for Diarrhea


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Should I treat diarrhea?

Most of the time, diarrhea doesn’t require treatment. It usually lasts only a couple of days, whether you treat it or not. However, medicine can help you feel better, especially if you also have cramping.

When diarrhea is a symptom of an infection caused by bacteria or parasites, antidiarrheal medicines can actually make the condition worse. This is because the medicine keeps your body from getting rid of the bacteria or parasite that is causing the diarrhea. Talk to your family doctor if you have any reason to think your diarrhea might be caused by a bacterial or parasitic infection.

Depending on the cause of your diarrhea, you may also need to take antibiotics prescribed by your doctor. Antibiotics are medicines that kill bacteria. If your doctor prescribes an antibiotic for you, it’s important to talk to your doctor before taking any over-the-counter (OTC) medicine to relieve your symptoms.

What types of OTC medicines treat diarrhea?

Over-the-counter medicines are medicines you can buy without a prescription from your doctor. Some OTC medicines can help you feel better if you have diarrhea. These are called antidiarrheal medicines.

Antidiarrheal medicines include loperamide (1 brand name: Imodium) and bismuth subsalicylate (2 brand names: Kaopectate, Pepto-Bismol). Bismuth subsalicylate can also be used for upset stomach and as an antiemetic (a medicine that treats nausea and vomiting).

How do OTC antidiarrheal medicines work?

Loperamide works by slowing down how fast things move through your intestines (bowels). This allows more fluid to be absorbed so that you have less diarrhea and more formed stools.

Bismuth subsalicylate works by balancing the way fluid moves through your intestines. It also reduces inflammation and keeps certain bacteria and viruses that cause diarrhea from growing in the stomach and intestines.

Who shouldn't take OTC antidiarrheal medicines?

Don’t give loperamide to children 2 years of age or younger unless your family doctor says it’s okay. It’s probably a good idea to check with your doctor before using loperamide for older children as well.

You shouldn’t take loperamide if you have a fever, or if you’ve ever had a rash or an allergic reaction after taking it. Don’t take loperamide if you have bloody or black stools. These may be signs of a more serious problem, including a bacterial infection, so talk to your family doctor.

People who are allergic to aspirin or other salicylate medicines should not take bismuth subsalicylate. Don’t give bismuth subsalicylate to children 12 years of age or younger. Don’t give bismuth subsalicylate to children or teenagers 12 to 18 years of age who may have the flu or chickenpox. This increases their risk for Reye syndrome, which is a serious illness that can lead to death.

How do I safely take OTC antidiarrheal medicines?

Read the directions on the drug facts label to learn how much medicine to take and how often to take it. If you have any questions about how much medicine to take, call your family doctor or pharmacist. Keep a record (1-page PDF; About PDFs) of which OTC medicines you are using and when you take them. If you need to go to the doctor, take this list with you.

Follow these tips to make sure you are taking the right amount of medicine:

  • Take only the amount recommended on the medicine’s label. Don’t assume that more medicine will work better or quicker. Taking more than the recommended amount can be dangerous.
  • If you are taking a prescription medicine, ask your doctor if it’s okay to also take an OTC antidiarrheal medicine.
  • Don’t use more than 1 OTC antidiarrheal medicine at a time unless your doctor says it’s okay. They may have similar active ingredients that add up to be too much medicine.

How can I safely store OTC antidiarrheal medicines?

Store all medicines up and away, out of reach and sight of young children. Keeping medicines in a cool, dry place will help prevent them from becoming less effective before their expiration dates. Do not store medicines in bathrooms or bathroom cabinets, which are often hot and humid.

What are some common side effects of OTC antidiarrheal medicines?

Healthy adults usually don’t experience side effects from antidiarrheal medicines. However, side effects may be a concern for older adults or people who have health problems. Call your doctor if you notice any side effects.

  • Loperamide side effects may include:
    • Abdominal pain
    • Constipation
    • Dizziness
    • Nausea or vomiting
  • Bismuth subsalicylate side effects may include:
    • Constipation
    • Blackened stools and/or tongue
    • Ringing sound in the ear (called tinnitus)

Can OTC antidiarrheal medicines cause problems with any other medicines I take?

Using any of the following medicines with loperamide can increase your risk for side effects, so your doctor may need to adjust your dosages. Ask your doctor before taking loperamide if you also take:

  • Antibiotics
  • Antiviral medicines for human immunodeficiency virus (HIV)
  • Prescription pain medicines

Bismuth subsalicylate may affect some medicines so that they don’t work as well.  It also may cause side effects if combined with other medicines. Ask your doctor before taking bismuth subsalicylate if you also take:

  • Blood-thinning medicines
  • Medicines for gout
  • Medicines for arthritis
  • Medicines for diabetes

Ask your doctor before taking bismuth subsalicylate if you take pain relievers or cold medicines. These medicines may contain aspirin, which is a salicylate. You may get too much salicylate if you take more than 1 of these medicines at a time.

When should I call my doctor?

If you have a fever, mucus or blood in your stools, or a history of liver disease, or you are taking prescription medicine, talk to your doctor before taking an antidiarrheal medicine.

 

 

Funding and support for this material have been provided by the Consumer Healthcare Products Association.

Written by familydoctor.org editorial staff

Reviewed/Updated: 10/13
Created: 09/05

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