Loperamide (Imodium®)
Pronounce: loe-PER-a-mide
Classification: Anti-diarrheal
About Loperamide (Imodium®)
Loperamide is a treatment to relieve diarrhea. It binds to the opiate receptor in the gut wall, which slows or stops 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 for byproducts of digestion to move through your intestine. Your body can hold on to more fluid and sodium, and this helps make your stools less soft. It also increases the tone of the anal sphincter, which reduces incontinence and urgency.
How to Take This Medication
Loperamide comes as a caplet, softgel, and liquid solution, all of which are taken by mouth. The dose and how often you take this medication depends on your treatment and how severe your diarrhea is. Ask your provider 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, 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 happen.
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, if you have black stool, or mucous or blood in your stool without first talking with your provider. You may need to have your stool tested for certain infections before taking this medication, so tell your provider that you are having diarrhea before 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?
Some cancer medications are only available through specialty pharmacies. Your provider or pharmacist will start this process. Your insurance plan may also affect where you can get your medication. Call your prescription plan provider to find out which specialty pharmacies are in-network.
Insurance Information
This medication may be covered by your prescription plan. If you qualify, you may be able to get financial help through patient assistance programs (PAP). Co-pay cards may also be available to lower your out-of-pocket cost if you have commercial (not Medicare/Medicaid/Tricare) insurance. Your pharmacist, social worker, or navigator can help find resources for financial support.
Possible Side Effects
These are some of the most common or most serious side effects of this medication. Talk with your provider about the side effects you are having and how they can be managed.
Constipation and Belly Cramps
Constipation is when you have less bowel movements than usual or are having trouble passing stool. This medication can cause constipation and abdominal (belly) cramps. If you are having these side effects, tell your provider.
Reproductive Concerns
Talk to your provider before becoming pregnant, getting someone pregnant while taking this medication, or before breastfeeding while receiving this medication.
Central Nervous System (CNS) Effects
This medication may cause drowsiness, fatigue, sedation, dizziness, and weakness. If these effects make it hard to carry out daily life, talk with your provider.
QT Prolongation with Torsades de pointes (TdP)
QT prolongation is when your heart is not working how it should, causing abnormal heartbeats or an abnormal heart rhythm. QT prolongation happens when the electrical signal to the lower chambers of your heart (ventricles) takes too long (prolonged), causing a period of time where these chambers don’t know what to do. During this time, the lower chambers can beat too fast and out of control while waiting for the correct signal.
Torsades de pointes (TdP) happens when the lower chambers start to beat out of control or dangerously fast. This stops your heart from being able to pump enough blood to your body and brain, which can cause fainting or seizures. If not treated right away, TdP can cause your heart to stop beating correctly and can make your heart stop. Call 911 right away if you feel abnormal heartbeats, if your heart is beating fast, or if you feel dizzy or faint.
Stomach Problems
In addition to constipation and abdominal cramps, loperamide can also lead to abdominal distension (swelling and firmness) and blood in the stool. If any of these symptoms develop, stop using loperamide and contact your provider right away to make sure you are not having a more serious side effect, such as a blockage of your intestine, megacolon, or toxic megacolon.
Dehydration and Electrolyte Changes
This medication can affect the normal levels of fluid and electrolytes (potassium, magnesium, calcium, etc.) in your body. Your providers will use blood tests to make sure these levels aren’t too high or too low.
If your levels become too low, there are certain electrolytes or fluids your provider can give you by IV or that you can take by mouth. Tell your provider before taking any supplements.
Toxic Megacolon
Toxic megacolon is when your colon swells and toxins go into your bloodstream. This is a serious condition. If you have ulcerative colitis (UC), this medication can raise your risk of toxic megacolon. Symptoms of toxic megacolon can be pain, bloating, or tenderness of your abdomen (belly), fever, fast heart rate (tachycardia), bloody diarrhea, and painful bowel movements.