Antidiarrhoeals

Antidiarrhoeals are a group of medications used to treat diarrhea. Diarrhea is a condition characterized by the frequent passage of loose or watery stools, which can lead to dehydration and electrolyte imbalance. Antidiarrhoeal drugs work by various mechanisms to reduce the frequency of bowel movements or to solidify the stool. They are used in the management of both acute and chronic forms of diarrhea, regardless of the underlying cause.

Types of Antidiarrhoeals

Antidiarrhoeals can be classified into several categories based on their mechanism of action:

Absorbents

Absorbents such as Bismuth subsalicylate and Activated charcoal work by binding to the causative agents of diarrhea, such as bacteria and toxins, and removing them from the gastrointestinal tract.

Opiates and Opiate Derivatives

Opiates like Loperamide (Imodium) and Diphenoxylate (Lomotil) slow down the movement of the gut. This allows more time for water and electrolytes to be absorbed, resulting in firmer stools.

Bile Acid Binders

Bile acid binders, such as Cholestyramine, are used to treat diarrhea caused by excessive bile acids in the colon.

Serotonin 5-HT3 Receptor Antagonists

Drugs like Alosetron are used specifically for Irritable Bowel Syndrome (IBS) with diarrhea. They work by blocking serotonin receptors in the gut, reducing bowel movement frequency.

Intestinal Flora Modifiers

Probiotics, such as Lactobacillus species, help restore the natural balance of flora in the intestine, which can be beneficial in treating diarrhea, especially when it's caused by antibiotic use.

Indications

Antidiarrhoeal medications are indicated for the relief of symptoms of acute diarrhea, such as that caused by a viral or bacterial infection, and for the management of chronic diarrhea, such as that associated with conditions like IBS or inflammatory bowel disease (IBD).

Contraindications

Antidiarrhoeals should not be used in cases where the diarrhea is caused by certain types of infections, such as those caused by certain bacteria (e.g., Clostridium difficile) or parasites, as slowing down the gut movement can worsen the condition. They are also contraindicated in patients with a history of hypersensitivity to the drug.

Side Effects

Common side effects of antidiarrhoeal medications include constipation, dizziness, and dry mouth. More serious side effects, though rare, can include toxic megacolon or intestinal obstruction.

Precautions

When using antidiarrhoeals, it's important to maintain adequate hydration, especially in children and the elderly, to prevent dehydration. If diarrhea persists for more than 48 hours or is accompanied by high fever, blood in the stool, or severe abdominal pain, medical advice should be sought.

See Also

• Gastrointestinal tract
• Dehydration
• Electrolyte imbalance
• Probiotics