Anti diarrhoeal drugs- introduction with ‘7’ classification

Anti diarrhoeal drugs

A prevalent digestive disorder called diarrhea is typified by frequent, loose, or watery stool motions. Numerous things can trigger it, including as bacterial or viral infections, food poisoning, adverse drug reactions, dietary modifications, or underlying medical problems like inflammatory bowel disease (IBD) or irritable bowel syndrome (IBS). Diarrhea can cause severe disruptions to everyday life, including pain, dehydration, and potentially serious consequences if left untreated, regardless of the reason.

Many anti-diarrheal medications have been created in reaction to the upsetting symptoms of diarrhea in order to lessen its effects and offer comfort to individuals who are afflicted. These drugs function in a variety of ways to treat the underlying cause of the diarrhea, lessen inflammation, or slow down intestinal movement.

Loperamide, marketed over-the-counter as Imodium, is one of the most popular anti-diarrheal medications. Loperamide functions by reducing intestinal motility, which promotes increased water absorption and harder stools. It works especially well for acute episodes of diarrhea brought on by a variety of conditions, such as viral infections or poor dietary choices.

Another popular anti-diarrhea drug that can be found in goods like Pepto-Bismol is bismuth subsalicylate. Because of its dual anti-inflammatory and antibacterial qualities, it works well to ease cramping in the abdomen, lessen diarrhea caused by specific germs, and reduce the frequency of bowel movements.

A prescription drug called diphenoxylate/atropine is frequently saved for episodes of diarrhea that are more severe. This combo medication acts by decreasing gastrointestinal motility and delaying intestinal contractions. Atropine is a component in the formulation to deter diphenoxylate misuse because it is an opioid derivative with the potential to become addicted.

Another family of anti-diarrheal medications, kaolin and pectin, function by absorbing water in the intestines and thickening the stool, which lowers the frequency and fluidity of bowel movements. They can be helpful, especially in mild bouts of diarrhea, even though they are not as frequently used as certain other drugs.

Apart from conventional drugs, probiotics have drawn interest due to their possible application in the treatment of diarrhea. Probiotic strains like Lactobacillus and Saccharomyces boulardii have the ability to improve intestinal barrier strength, balance gut flora, and reduce diarrhea symptoms.

Anti-diarrheal medications relieve symptoms, but it’s important to understand that they don’t treat the underlying cause of diarrhea. Consequently, in addition to using them, efforts should be made to determine and address the condition’s underlying cause. Furthermore, quick medical assistance should be sought in situations when diarrhea lasts longer than a few days, is accompanied by severe symptoms like fever or dehydration, or affects vulnerable groups like the elderly or small children.

Anti diarrhoeal drugs classification:

Anti-diarrheal drugs can be classified into several categories based on their mechanisms of action and chemical properties. Here’s a classification of anti-diarrheal drugs:

1.Opioid Agonists:

Opioid agonists are a type of medication used to alleviate diarrhea by reducing intestinal motility and decreasing the frequency of bowel movements. Loperamide, available over-the-counter, functions by binding to opioid receptors in the gastrointestinal tract, notably in the intestinal wall. This binding slows down peristalsis and extends transit time, allowing for increased water absorption, resulting in firmer stools and fewer bowel movements. It is effective for various types of acute diarrhea, including traveler’s diarrhea and that associated with gastroenteritis. Diphenoxylate, another opioid derivative, acts similarly to loperamide but carries a risk of addiction. Therefore, it is usually combined with atropine, a muscarinic antagonist, to deter misuse. Atropine, in small doses, induces unpleasant side effects if the medication is abused. This combination is used to treat both acute and chronic diarrhea symptoms. While opioid agonists are generally safe and effective for short-term diarrhea management, they are not recommended for certain cases, such as diarrhea caused by bacterial or parasitic infections, as they can prolong illness by slowing pathogen elimination. Caution is advised when using opioid agonists in patients with specific medical conditions, like inflammatory bowel disease or liver dysfunction, as they may exacerbate underlying issues. Proper usage as directed by a healthcare provider is crucial, and any adverse effects should be reported promptly.

2.Bismuth Subsalicylate:

Bismuth subsalicylate is a compound that blends bismuth, a heavy metal, with salicylic acid, a derivative of aspirin. It’s commonly used without a prescription to alleviate gastrointestinal distress symptoms like diarrhea, indigestion, and nausea.

Its mechanism of action involves several aspects:

  1. Anti-inflammatory: Salicylic acid, present in bismuth subsalicylate, possesses anti-inflammatory properties that help reduce inflammation in the gastrointestinal tract, easing symptoms like abdominal discomfort and diarrhea.

  2. Antimicrobial: Bismuth subsalicylate exhibits mild antibacterial properties, which can hinder the growth of certain bacteria responsible for diarrhea, aiding in its resolution.

  3. Protective Coating: It forms a protective layer over the stomach and intestinal lining, soothing irritation and shielding mucous membranes from further harm, offering relief from nausea and indigestion.

  4. Absorbent Properties: Bismuth subsalicylate binds to toxins and excess fluids in the gut, absorbing them to promote firmer stools, thus reducing diarrhea symptoms.

Available in various forms such as tablets and liquids, it’s sold under brand names like Pepto-Bismol and Kaopectate. Dosage recommendations vary based on formulation, age, and medical condition.

Though generally safe for short-term use, it’s not suitable for everyone. Individuals with certain conditions like aspirin sensitivity, kidney disease, or gout should consult a healthcare professional. Prolonged or excessive use can lead to side effects like constipation and rare but severe reactions like Reye’s syndrome in children, so it’s crucial to use it as directed and seek medical advice if symptoms persist or worsen.

3.Intestinal Adsorbents:

Intestinal adsorbents belong to a category of anti-diarrheal drugs designed to alleviate diarrhea symptoms by absorbing toxins and excess water in the digestive tract. Their primary mode of action involves binding to substances like bacteria and toxins in the intestines, subsequently removing them from the body through stool. A widely used combination includes kaolin and pectin, where kaolin, a clay mineral, has significant adsorptive capacity, while pectin, a soluble fiber from fruits, contributes to stool bulk and consistency by forming a gel-like substance. These combinations are available in various forms like powders, suspensions, and chewable tablets for oral consumption. While generally safe and effective for mild to moderate diarrhea, caution is advised, especially in severe cases or when accompanied by other symptoms. Consulting a healthcare professional before use is recommended, particularly for individuals with existing medical conditions or those taking other medications, to avoid potential interactions or exacerbation of underlying health issues.


Probiotics, live microorganisms including bacteria and yeast, offer health advantages when consumed in sufficient quantities. These beneficial bacteria are naturally present in the gut and play a vital role in maintaining gut health and overall wellness. They can be obtained from certain foods like yogurt, kefir, sauerkraut, and kimchi, as well as through supplements.

Their main role is to promote a healthy balance of gut microbiota, crucial for proper digestion, nutrient absorption, immune function, and defense against harmful pathogens. Probiotics achieve this by competing with pathogens for resources in the gut, producing beneficial substances like short-chain fatty acids and vitamins, modulating immune function, improving digestive health, and potentially supporting mental well-being.

Common probiotic strains such as Lactobacillus acidophilus, Lactobacillus rhamnosus, Bifidobacterium bifidum, Bifidobacterium longum, and Saccharomyces boulardii have been extensively researched for their health benefits and are found in many probiotic products.

While generally safe, individuals with compromised immune systems or underlying medical conditions should consult healthcare professionals before taking probiotic supplements. The effectiveness of probiotics may vary based on factors like strain, dosage, duration of use, and individual health status, emphasizing the importance of selecting probiotic products carefully and following recommended guidelines for optimal results.


Racecadotril is a medication mainly prescribed to treat acute diarrhea in adults and children. Unlike traditional anti-diarrheal drugs that work by slowing intestinal movement, racecadotril functions differently.

It acts as an enkephalinase inhibitor, targeting an enzyme that breaks down natural opioid peptides in the gut, like enkephalins. These peptides normally help regulate fluid levels in the intestine. By inhibiting enkephalinase, racecadotril boosts the concentration of these opioids, reducing fluid secretion and enhancing fluid absorption.

This leads to a decrease in stool volume and liquidity, relieving diarrhea symptoms. Unlike opioid-based medications, racecadotril doesn’t significantly penetrate the blood-brain barrier, so it doesn’t cause typical opioid side effects like sedation or dependence.

It’s often used alongside rehydration measures for acute diarrhea caused by infections or gastrointestinal issues. It addresses the underlying causes of diarrhea without overly slowing bowel movements. Side effects are rare and mild, including nausea, abdominal pain, and gas. Racecadotril comes in various forms for easy use in adults and children.

Like any medication, it should be used under medical supervision, following prescribed dosage and duration. If diarrhea persists despite treatment, medical attention is advised for further evaluation or alternative therapies.

6.Antimotility Agents

Antimotility agents constitute a category of medications primarily employed to address diarrhea by retarding the movement of the intestines. These agents function by impeding intestinal muscle contractions, thereby decelerating the transit of food through the digestive tract. This slowdown facilitates increased water absorption and the formation of more solid stools, ultimately alleviating diarrhea symptoms. Among the key antimotility agents, loperamide stands out.

Loperamide, a synthetic opioid receptor agonist, predominantly targets the mu-opioid receptors in the intestinal wall. Widely accessible over-the-counter, it is frequently used for acute diarrhea treatment. Loperamide operates by diminishing peristalsis and enhancing intestinal muscle tone, thus reducing the pace of gastrointestinal content movement. This extension of time aids fluid absorption in the intestines, resulting in firmer stools and a decrease in diarrhea frequency and urgency.

Unlike conventional opioids, loperamide exhibits limited effects on the central nervous system due to its poor ability to cross the blood-brain barrier, thus reducing the likelihood of inducing euphoria or respiratory depression even at elevated doses. However, it is imperative to adhere to recommended usage, as misuse or excessive intake may still lead to adverse effects.

While generally well-tolerated, loperamide, like any medication, may produce side effects such as constipation, abdominal discomfort, nausea, and dizziness. Certain conditions, including acute dysentery, bacterial enterocolitis, and pseudomembranous colitis, contraindicate its use. Additionally, caution is warranted in patients with liver disease or those taking medications that could interact with loperamide.

Although effective for managing acute diarrhea, loperamide is unsuitable for prolonged use or specific types of diarrhea, such as those stemming from bacterial infections or inflammatory bowel disease. In such instances, addressing the underlying cause of diarrhea is crucial for appropriate management.

In summary, antimotility agents like loperamide play a significant role in alleviating diarrhea symptoms by slowing intestinal motility. Nonetheless, their judicious use under healthcare professional guidance is paramount to ensure safe and effective diarrhea management.

7.Antibiotics (in certain cases):

In situations of bacterial diarrhea brought on by particular pathogens, such as particular strains of Salmonella or Escherichia coli, antibiotics may be recommended. By focusing on the underlying bacterial illness, these medicines help to treat diarrhea. They are, however, often saved for certain purposes and are not utilized as first-line therapy for the majority of episodes of diarrhea.


In summary, anti-diarrheal medications are helpful in controlling diarrhea symptoms and enhancing the lives of those who are afflicted. To provide proper care and monitoring, their usage should be supervised by medical specialists, especially in situations when diarrhea is chronic or linked to aggravating problems.

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