Loperamide – Effective antidiarrheal for acute and chronic diarrhoea.
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What is Loperamide?
Loperamide is a highly effective antidiarrheal medication that provides rapid relief from both acute and chronic diarrhoea. Its selective action on gut opioid receptors means it controls diarrhoea without significant central nervous system effects, making it safe for most people.
Book an online consultation if you’re experiencing persistent diarrhoea, have been diagnosed with IBS with diarrhoea, or need management for chronic digestive conditions. Our GPs can assess your symptoms and determine if Loperamide or other treatments are appropriate for your specific bowel condition.
What is Loperamide used for?
- Acute diarrhoea
- Chronic diarrhoea
- Irritable bowel syndrome with diarrhoea (IBS-D)
- Inflammatory bowel disease symptom management
- Traveller's diarrhoea
- Post-operative diarrhoea
- Ileostomy output reduction
How does Loperamide work?
An opioid receptor agonist that slows intestinal motility by acting on μ-opioid receptors in the gut wall, increasing water and electrolyte absorption and reducing stool frequency.
Dosage and Administration
Adults
Initial dose 4mg, then 2mg after each loose stool. Maximum 16mg daily. For chronic conditions: 2-16mg daily in divided doses.
Children
Children over 4 years: weight-based dosing—specialist advice often required.
Important Notes
- Take with water, can be taken with or without food.
- For acute diarrhoea: stop when normal stools return or after 48 hours without loose stools.
- For chronic conditions: take regularly as prescribed.
- Available over-the-counter for short-term use.
Side Effects
Common Side Effects
- Constipation (especially with overuse)
- Abdominal pain or cramps
- Nausea
- Dizziness
- Drowsiness
- Flatulence
Serious Side Effects
Seek immediate medical attention if you experience:
- Severe constipation or bowel obstruction
- Toxic megacolon (in inflammatory bowel disease)
- Severe abdominal distension
- Heart rhythm changes (with very high doses)
- Severe allergic reactions (rare)
Important Warnings
- Do not use if you have bloody diarrhoea, high fever, or severe abdominal pain.
- Not suitable for children under 4 years or those under 35kg weight.
- Use with extreme caution in inflammatory bowel disease—can cause toxic megacolon.
- Stop immediately if constipation, abdominal distension, or severe abdominal pain develops.
- Seek medical attention if diarrhoea persists for more than 48 hours.
Drug Interactions
Tell your GP if you're taking any of the following medications:
- Generally few significant drug interactions.
- P-glycoprotein inhibitors—may increase loperamide levels.
- Quinidine—may increase loperamide absorption.
- Generally safe to use with most other medications.
Frequently Asked Questions
How quickly does Loperamide work?
Loperamide usually starts working within 1-2 hours, with maximum effects typically seen within 4-6 hours of taking a dose.
Can I take Loperamide for food poisoning?
Generally not recommended for infectious diarrhoea as it may prolong the infection by preventing the body from eliminating bacteria or toxins.
Is it safe to take Loperamide long-term?
For chronic conditions like IBS, long-term use under medical supervision is generally safe, but regular review is important to ensure continued appropriateness.
Why shouldn't I use Loperamide if I have bloody diarrhoea?
Bloody diarrhoea may indicate serious infection or inflammatory bowel disease where slowing gut motility could worsen the condition or cause complications.
Medically Reviewed by: Mohammed Hassan - Independent Prescriber
Last Updated: 2025-01-14