Loperamide: Use, Dosage, Warnings, and Side-Effects

loperamide hydrochloride

Usually known as Imodium, is a medication used to treat diarrhea and similar conditions.

Paul Janssen, a Belgian physician, and Founder of a pharmaceutical company that created many drugs invented this medication in 1973.

Dr. Janssen synthesized this drug by using his previous work from 1956 on diphenoxylate hydrochloride, and his discovery of fentanyl citrate in 1960, to create a safe and effective antidiarrheal.

As a result, Loperamide works like an analgesic that slows the rhythm of digestion allowing the intestines to absorb more fluids and nutrients from the food people consume.

After successful clinical tests, Dr. Janssen launched Loperamide as Imodium in that same year. But it would take until 1976 for the Food and Drug Administration (FDA) agency to approve the medication.

Usually, Loperamide is available in the form of capsules and oral solution.


Loperamide affects the enteric nervous system, a quasi-autonomous part of the nervous system (almost like a second brain) that regulates gastrointestinal functions.

It decreases the secretory and motility functions of the intestine by suppressingĀ peristaltic contractions, and that allows the bowel to absorb more fluids from fecal matter.

Put in simpler terms, Imodium slows down the movement of the gut making stool less watery.

Loperamide also reduces the number of discharges in people who undergo an Ileostomy (a surgical opening in the abdominal wall, from which the end of the small intestine will expel its matter).

However, it’s worth noting that Imodium only alleviates the symptoms of diarrhea. This medication doesn’t eliminate the cause.

Loperamide Dosage

The prescribed dose for each case varies depending on the circumstances and age of the patients.

For examples, for adults with Acute Diarrhea, the recommended initial dose is 4mg of Loperamide after every unformed stool.

However, patients should be careful not to consume an amount beyond the 16mg daily.

When it comes to kids with Acute Diarrhea, the amount will vary depending on their weight and age.

Children between the ages of 2 to 5 years, weighing around 20kg or less, should take a dose of 7.5 ml of the Imodium oral solution three times a day.

For kids between the ages of 6 to 8 years, weighing 20 to 30 kg, years can use either the oral solution or the capsules.

If patients choose liquid medication, they should take 15 ml two times a day; if they use capsules instead the amount should be 2 mg two times a day.

For children between the ages of 8 to 12 years, weighing above 35 kg, the prescribed dose would be either 15 ml (oral solution) or 2mg (capsules), three times a day.

In cases of Chronic Diarrhea, the dose would be 2mg two times a day for adults. Which, depending on clinical improvement, doctors may reduce to only 2mg daily or increase to 2mg for times a day.

When it comes to kids, medical experts will consider which amount would be the best dose for the patients.


Before taking this medication, patients should take several tests to confirm the cause of their diarrhea.

People with Ulcerative Colitis, a disease that causes inflammation and irritation in the colon, should avoid taking Loperamide.

Patients that take more than the recommended dose of Imodium can develop severe and potentially deadly heart issues.

People should avoid giving Imodium to kids younger than two years old.

Patients must carefully follow the instructions of their healthcare provider when it comes how much and how often they should take Loperamide.

They have to consult with the doctor before taking another medication along with Imodium, as mixing it with other drugs may cause adverse effects.

However, when people’s symptoms include bloody or tarry stools along with high fever, doctors will likely avoid using Loperamide.

For cases of patients with Hepatic Impairment, medical experts should proceed with caution given the effects Imodium has on the metabolism.

Loperamide DosageĀ Side-Effects

More often than not, patients display no unwanted effects. But, if such things occur, people must consult their doctor as soon as possible.

Although they’re pretty rare, here’s a list of the possible side-effects from taking Loperamide:

  • Abdominal bloating due to the gastrointestinal tract getting filled with gas.
  • Constipation, which means lacking bowel movement.
  • Loss of appetite
  • Severe stomach pain along with nausea and vomiting
  • Skin rashes, a possible allergic response that manifests as redness and itchiness in the skin.
  • Dizziness or drowsiness
  • Dry mouth
  • Tachycardia, which means fast/irregular heart rate
  • Fainting
  • Difficult breathing