Loperamide (Imodium®) – Oral

Author: OncoLink Team
Last Reviewed: July 21, 2022

Pronounce: loe-PER-a-mide

Classification: Anti-diarrheal

About: Loperamide (Imodium®) – Oral

Loperamide works in a few ways to lessen diarrhea. It binds to the opiate receptor in the gut wall which inhibits the release of acetylcholine and prostaglandins. By doing this it slows down peristalsis (movement of your intestinal muscles) and increases the amount of time it takes the byproducts of digestion to move through your intestine. Your body is able to retain more fluid and sodium and helps make your stools less soft. It also increases the tone of the anal sphincter which reduces incontinence and urgency.

How this Medication Comes

Loperamide comes as a caplet, softgel, and liquid solution, all of which are taken by mouth.

How to Take Loperamide

The dose and how often you take this medication depends on your treatment and how severe your diarrhea is. Ask your care team what your dose will be and how often you should take the medication.

It is important to make sure you are taking the correct amount of medication every time. Before every dose, check that what you are taking matches what you have been prescribed. If using the oral solution, shake well before taking the medication. If you take more than what has been prescribed for you or what is suggested on the product packaging you should call Poison Control Center at 1-800-222-1222. This medication should not be given to children less than 2 years of age as cases of severe respiratory depression and coma can occur.

You should not drive a car or operate heavy machinery until you know how this medication affects you.

You should not take this medication if you have a fever or mucous or bloody or black stool without first consulting with your provider. You may need to have your stool tested for certain infections prior to taking this medication so you should tell your provider that you are having diarrhea prior to taking this medication.

Be sure to tell your healthcare provider about all medications and any herbal supplements you take. This medication can interact with other medications and supplements, including procainamide, amiodarone, sotalol, chlorpromazine, haloperidol, thioridazine, ziprasidone, moxifloxacin, pentamidine, methadone, itraconazole, gemfibrozil, quinidine, and ritonavir, among others.

This medication should not be taken if you have abdominal pain without diarrhea. Tell your provider if you have ever had problems with your bowels, including dysentery, ulcerative colitis, bacterial enterocolitis, or pseudomembranous colitis usually linked to broad-spectrum antibiotic use.

Storage and Handling

Store this medication in the original container. All forms of this medication should be stored at room temperature. The softgels should be protected from light. Keep this medication out of reach of children and pets. Dispose of any unused medication safely.

Where do I get this medication?

This medication is available over the counter at retail pharmacies or by prescription. Your oncology team will work with your prescription drug plan to identify an in-network retail/mail order pharmacy for medication distribution. 

Insurance Information

Loperamide may be covered under your prescription drug plan. Patient assistance may be available to qualifying individuals without prescription drug coverage. Co-pay cards, which reduce the patient co-pay responsibility for eligible commercially (non-government sponsored) insured patients, may also be available. Your care team can help you find these resources if they are available.

Possible Side Effects of Loperamide

This medication is given to manage and/or prevent side effects of your cancer treatment. If you are having side effects from this medication you should talk to your team about if this medication is necessary to your treatment or if there are other options to help manage the side effect this medication is treating. These are some of the most common side effects:

Constipation and Abdominal Cramps

Due to the way this medication works, it may lead to constipation and abdominal cramps. If you are experiencing these side effects after taking loperamide, stop taking the loperamide, and notify your provider.

Less common, but important side effects can include:

  • Central Nervous System (CNS) Effects: Loperamide may cause drowsiness, fatigue, sedation, dizziness, and weakness. If these effects make it hard to carry out daily life, talk with your provider.
  • Cardiac Events: When loperamide is taken in doses higher than what is recommended it can lead to cardiac events such as prolongation of QT/QTC interval and Torsades de Pointes, both of which can lead to cardiac arrest. This is rare, but if you have a history of cardiac issues you should discuss this with your provider. If you take more medication than suggested on the product packaging or what has been prescribed by your provider you should contact Poison Control Center at 1-800-222-1222.
  • Stomach Problems: In addition to constipation and abdominal cramps, loperamide can also lead to abdominal distension and blood in the stool. If any of these symptoms develop, stop using loperamide and contact your oncology care team immediately to make sure you are not having a more serious side effect such as a blockage of your intestine, megacolon, or toxic megacolon.
  • Allergic Reactions: In rare cases, allergic reactions have been associated with loperamide. If you have any symptoms of an allergic reaction such as a new rash, feeling faint, difficulty breathing, or new swelling in the face or throat you should contact your provider right away.

Reproductive Concerns

You should consult with your provider before becoming pregnant or fathering a child while on this medication. You should consult with your healthcare team before breastfeeding while receiving this medication.