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Imodium, the brand name of loperamide hydrochloride, is an antidiarrheal medication which is available over-the-counter without prescription.

Overview of Imodium - antidiarrheal medication

Imodium is an approved therapy for a number of diarrheal syndromes, including acute, infectious diarrhea, traveler's diarrhea and chemotherapy-associated diarrhea. It is effective in providing symptomatic control of chronic diarrhea such as that associated with chronic inflammatory bowel disease or following gastrointestinal surgery.

It is a derivative of phenylpiperidine and has chemical structure similar to opiate receptor agonists such as diphenoxylate. Loperamide and diphenoxylate are used to treat diarrhea in several types of inflammatory bowel disease. Loperamide was basically designed to minimize the negative aspects associated with opiate receptor agonists while sustaining the antidiarrheal activity. Therefore, it is preferable to diphenoxylate as it does not have the central nervous side effects of diphenoxylate. Imodium does not have any abuse potential and is generally well tolerated at recommended doses. The most common side effects are usually related to the impact on bowel motility.

The administration of Imodium is intended only to reduce the frequency of bowel movement. However, it will not kill the causative infectious organisms responsible for the diarrhea or lead to rehydration. Imodium should not be used in acute diarrhea associated with organisms that make a way into the intestinal mucosa or in pseudomembranous colitis related to use of broad-spectrum antibiotics. In addition, the use of Imodium does not exclude the administration of appropriate fluid and electrolyte therapy.

Imodium Mechanism of Action

Imodium works by a number of different mechanisms that reduce gastrointestinal peristalsis and fluid secretion. It decreases the activity of the intestinal myenteric plexus, which in turn reduces the tone of the longitudinal smooth muscles, and increases tone of circular smooth muscles of the intestinal wall. This action results in longer duration of gastrointestinal transit (movement) time and increases absorption of water and electrolytes from the intestinal tract. Further, it decreases the movement of colonic mass and restricts the gastrocolic reflex. Imodium also increases anal sphincter tone, thereby improving fecal continence in patients with diarrhea.

Nevertheless, it does not have any significant pain-relieving activity and does not reduce the pain associated with certain types of irritable bowel syndrome and diarrhea. It is not effective in diarrhea caused by cholera, Shigella or Campylobacter and it is contraindicated in diarrhea associated with organisms that can penetrate the intestinal walls, such as E. coli or salmonella. Common adverse reactions to Imodium include nausea and abdominal cramps. Treatment with Imodium should be avoided in cases of diarrhea related to the presence of fever or bloody stool (dysentery).

Benefits of Imodium

The following are the benefits of Imodium in the management of diarrhea:

  • Increases the absorption of fluids and electrolytes from the intestinal tract
  • Decreases the speed and frequency of intestinal contractions
  • Decreases intestinal fluid secretion
  • Increases the passage time of stool through the colon
  • Increases muscle tone in the anal sphincter

Use of Imodium in Children

The United States Food and Drug Administration (FDA) has approved the use of Imodium for children older than 2 years of age. However, the World Health Organization and few other health organizations such as the American Academy of Pediatrics have voiced concerns that Imodium may neither be safe, nor effective in young children.

In a systematic review and meta-analysis of randomized controlled trials in order to assess the efficacy and adverse effects of Imodium compared with placebo for acute diarrhea in children younger than 12 years of age, Imodium is shown to reduce the duration and frequency of diarrhea when used as an adjunct to the oral or intravenous rehydration in these patients. However, serious adverse events including lethargy, paralytic ileus, abdominal distension and death were reported in children younger than 3 years of age.

Therefore, the risk of serious adverse events probably outweighs the benefit of a potential 24-hours reduction in diarrhea duration among these children. In addition, the lowest efficacious dose should be used as Imodium appears to be effective in doses as low as 0.1 to 0.25 mg/kg/day, in order to reduce the risk of overdosing.

Dosage in Children

Recommended First Day Dosage

  • For age group of 3 to 5 years (13 to 20 kg): 1 mg thrice a day (3mg daily dose)
  • For age group of 6 to 8 years (20 to 30 kg): 2 mg twice a day (4mg daily dose)
  • For age group of 9 to 12 years (> 30 kg): 2mg thrice a day (6mg daily dose)

Recommended Subsequent Daily Dosage

The recommended subsequent dose of Imodium after the first day treatment should be administered at doses (1 mg/10 kg body weight), only after a loose stool. The total daily dosage should not exceed the recommended dosages for the first day.

Read More: How to Stop Diarrhea in Toddlers

The Bottom Line

Imodium is generally considered as a safe and effective therapy for the treatment of diarrhea in children above 3 years of age. Nevertheless, it is not recommended for dehydrated or malnourished children or in children experiencing bloody diarrhea. Before administering Imodium in children, the potential benefit of whether reducing the duration of diarrhea by a day is worth the potential risk of adverse events should be taken into consideration.

The combination of oral rehydration therapy and early nutritional support should remain the focus of management of diarrhea in children as it promises to safely and effectively assist a child through an episode of diarrhea. Imodium may be considered as an adjunct to this treatment in children older than 3 years with no or minimal dehydration.