Imodium: Uses and Side Effects

Imodium uses and side effects

Imodium (or Loperamide hydrochloride), is a synthetic anti-diarrheal for oral use. It is an over-the-counter(OTC) medication used to control acute diarrhoea. Imodium, also stylized as Imodium A-D, is the brand name for LOPERAMIDE (pronounced as loe per’ a mide). It works by slowing down an overactive bowel, which decreases the number of bowel movements. It can also be used to reduce the amount of stool in people who have an ileostomy (i.e., evacuation of stool from the ileum instead of the anus). This medicine is often used for a short period of time. Let’s pay some attention to Imodium uses and side effects.

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Mechanism of Action

Before we begin with the uses and side effects of Imodium, we need to understand its mode of action. Imodium (loperamide hydrochloride) acts by slowing intestinal motility and by affecting water and electrolyte movement through the bowel. It functions by binding to the opiate receptor in the gut wall. Therefore, it inhibits the release of acetylcholine and prostaglandins thereby, prolonging gastrointestinal transit time.  This tablet increases the tone of the anal sphincter hence, reduces incontinence and urgency. Loperamide reduces faecal volume, increases viscosity, bulk density, and decreases fluid and electrolyte volume depletion.

Imodium uses and side effects

Image source: Rivai, H., Puspita, R., & Misfadhila, S. (2018). Development and validation of loperamide hydrochloride tablet analysis method with absorbance and area under curve methods spectrophotometrically. Jurnal Sains Farmasi & Klinis, 5(2), 94-101.


Imodium is available in various dosage forms such as capsules, suspensions, gels, or tablets. You shouldn’t use Imodium for more than 2 days in a row.

For acute diarrhoea: 4mg orally followed by 2 mg after each loose bowel movement. The maximum dose to be taken is 16mg/day.

High Output Ileostomy: 4mg twice daily for 4 days. May then increase to 12 mg daily for 3 days.

Traveller’s Diarrhea: 4mg orally followed by 2mg after each loose bowel movement. The maximum dose to be taken is 8mg/day.

Adults: The recommended dosage is 4mg (two capsules) to start. This is followed by 2 mg (one capsule) after each loose stool. The daily dose should not exceed 16mg (eight capsules).

Children: For children, dosage should be based on weight or age.
  • Children between 27 to 43 kilograms: Daily dose should not exceed 6 mg/day
  • Children between 21 to 27 kilograms: Daily dose should not exceed 4 mg/day
  • Children between 13 to 21 kilograms: Only on the advice of a paediatrician
  • Children under 13 kilograms: Imodium should not be given

What happens if I miss a dose?

There’s no need to take stress in case you miss a dose. Take the missed dose as soon as you remember but in case it is almost time for the next dose. Skip the dose and continue your regular dosing plan. Do not take double doses at the same time.

What happens if I overdose?

There’s a rise in the number of cases of increasing overdoses of Imodium every year. Patients are using doses much higher than recommended to achieve systemic opioid effects with loperamide. These overdoses can lead to cardiac arrhythmias(fast or irregular heartbeats), fainting, or electrolyte imbalance. Therefore, an overdose of loperamide can be lethal.

Uses and Benefits

Loperamide hydrochloride (Imodium) is used to treat acute diarrhoea, including traveller’s diarrhoea. Patients with dysentery (diarrhoea with blood) should not be given this medicine. It gradually slows down the movement of the bowels and, therefore, decreases the number of bowel movements. It works by reducing the amount of flow of fluid and electrolytes. Loperamide is also used to reduce the amount of fluid in patients with ileostomies (to create an opening for the removal of wastes through the abdomen). It is also used to treat ongoing diarrhoea in people with inflammatory bowel disease (a condition in which the lining of all or part of the intestine is swollen, irritated, or has sores). Loperamide cannot treat the cause of diarrhoea but definitely treats its symptoms.


Imodium is indicated for the control and symptomatic relief of chronic diarrhoea associated with irritable bowel syndrome in adults. Also, for the acute non-specific diarrhoea in children of 2 years of age and older. In case of high output ileostomy, Imodium is used.


  • patients who are hypersensitive to loperamide hydrochloride(Imodium) or to any of its products
  • pediatric population less than 2 years of age due to the risk of various cardiac adverse reactions including sudden death ☠
  • patients having pseudomembranous colitis
  • patients having abdominal pain in the complete absence of diarrhoea
  • patients having acute ulcerative colitis
  • patients having bacterial enterocolitis

Side Effects

Imodium can sometimes lead to many side effects.

Here are some of the most common side effects of Imodium:

  • vomiting
  • constipation
  • dizziness
  • headache
  • nausea
  • drowsiness
  • skin rash, itching etc.

Now are some of the most serious side effects of Imodium:

  • swelling or pain in the abdomen
  • bloody or worsening diarrhoea
  • the uncomfortable feeling of fullness of stomach or abdomen
  • serious heart symptoms like fast, irregular, or pounding heartbeats
  • eye symptoms may include blurred vision, sudden vision loss
  • severe allergic reactions including difficulty breathing

Drug Interactions

Imodium is known to interact with several drugs. These drug interactions may increase the risk of cardiac adverse reactions and cause sudden death. It happens especially in patients who are already taking enzyme inhibitors or patients with underlying cardiac conditions. Imodium also interacts in case you have bloody stools, allergic reactions, ulcerative colitis (inflammation of the colon), renal impairment, or hepatic impairment. If taken along with alcohol may lead to excessive drowsiness or sleepiness.

Here is a list of some of the drugs:

  • Itraconazole
  • Gemfibrozil
  • Quinidine
  • HIV drugs like ritonavir
  • Diphenhydramine
  • Erythromycin

Information for patients

Doctors must inform patients about Imodium uses and side effects.

1. Do not take more than the prescribed dosage of Imodium. A higher dose than that prescribed may lead to adverse cardiac reactions such as fast, irregular heartbeats.

2. Do not take Imodium if you have bloody or tarry stools. It may be due to some other problem in the digestive tract.

3. If diarrhoea is followed by fever, avoid taking Imodium.

4. Take Imodium with acute diarrhoea. If no clinical improvement is observed within 48 hours, discontinue taking Imodium.

5. Imodium should be taken with great caution in the pediatric population because of the greater variability in this age group. In addition, dehydration at this age may further influence the variability of response to Imodium.

6. Use caution while driving as there can be tiredness, and drowsiness during the settling of diarrheal symptoms after taking Imodium.

7. Tell their doctor or pharmacist about all the over-the-counter medications they are taking besides Imodium to avoid any drug-to-drug interaction.

8. It is important to make a list of all the prescription and nonprescription medicines you’re taking and carry with you every time you visit the doctor.

Final words

Imodium is an effective OTC drug for people suffering from acute diarrhoea. It contains loperamide hydrochloride which functions by decreasing the muscular contractions in the GIT (gastrointestinal tract). There can be many side effects, they can be both mild as well as serious. To avoid the various side effects, it’s better to read all the instructions given on the label and carefully follow them. Try not to skip any dose or take a double dose. So to conclude Imodium uses and side effects, it should be taken in the prescribed dosage amount.

If there is still anything that’s bothering you, feel free to talk to your doctor or pharmacist. Seek attention if your diarrhoea gets worsen or there is no clinical improvement after 48 hours of taking this medication.

Thanks for reading!


  1. Arnold, C., & Martinez, C. J. M. (2019). Loperamide overdose. Cureus11(5). Loperamide Overdose – PMC (


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