Loperamide

What is Loperamide?

Loperamide is a Pharmacy Only Medicine in Hong Kong widely used to control the symptoms of acute and chronic diarrhoea. It is not intended to treat the underlying cause of an infection but helps manage frequent bowel movements while the body recovers.

It is a synthetic opioid agonist, but unlike traditional opioids, it is designed to act locally on the mu-opioid receptors within the intestinal wall. By binding to these receptors, it decreases the speed of bowel movements, allowing for increased absorption of water and electrolytes to improve stool consistency.

Generic Names:

• Loperamide: Widely used globally as a standard generic antidiarrheal agent.
• Loperamide hydrochloride: The full chemical name used in medical contexts and pharmaceutical formulations.

Global Brand Names:

Several pharmaceutical brands manufacture Loperamide for global distribution.

• Imodium (易蒙停): A common global brand widely registered and available in Hong Kong pharmacies.
• Loperamide-Sandoz: Registered generic version available in Hong Kong.
• Pms-Loperamide: Commonly dispensed generic in both private and public healthcare sectors in Hong Kong.

These names all refer to the same medication. It's important to note that while the active ingredient is the same, different countries may have different regulations and available medication formulations.

What is Loperamide used for?

Loperamide is used to relieve:

• Acute, non-specific diarrhoea
• Chronic diarrhoea associated with inflammatory bowel disease (IBD)
• High volume discharge from ileostomies

How do you use Loperamide?

Availability:

• Capsules
• Tablets

Dosage Information:

• Adults: Take 4mg initially, followed by 2mg after each loose stool, up to a maximum of 8mg per day without a prescription (or 16mg under strict medical supervision).
• Children (6-12 years): Dosage varies by age and weight; use only under medical advice.
• Children (under 2 years): Do not use.

Suitability:

• Adults: Yes, for managing symptoms of diarrhoea.
• Children aged 6 and older: Yes, but only under medical advice.
• Infants under 2 years: No, high risk of severe complications.

Who cannot take Loperamide?

Allergies and unsuitability:

• Rare, but possible allergic reactions.

Conditions where the drug should not be used:

• Known hypersensitivity to Loperamide
• Acute dysentery (characterized by blood in stools and high fever)
• Acute ulcerative colitis
• Bacterial enterocolitis (e.g., caused by Salmonella, Shigella, Campylobacter)
• Pseudomembranous colitis associated with broad-spectrum antibiotics
• Conditions where avoiding constipation or bowel blockage is critical

Common side effects of Loperamide include constipation, flatulence, headache, dizziness, and nausea. These generally subside as the body processes the medication and diarrhoea resolves.

Severe but rare adverse reactions include toxic megacolon, severe allergic reactions (angioedema), and paralytic ileus. Taking higher than recommended doses poses a serious risk of cardiac adverse events, including QT interval prolongation, irregular heart rhythms, and cardiac arrest. Discontinue use and seek medical help if severe abdominal pain, high fever, or heart palpitations occur.

• Do not exceed the daily maximum dose to avoid the risk of severe cardiac events.
• Avoid taking Loperamide if you have a high fever or bloody stools, as this may indicate a severe bacterial infection.
• Stop taking the medication if your symptoms do not improve within 48 hours and consult a doctor.
• Do not use in children under two years old due to the risk of respiratory depression and paralytic ileus.
• Drink plenty of fluids and electrolytes, as Loperamide does not treat or prevent dehydration.
• Check with a doctor if you take P-glycoprotein inhibitors (like ritonavir or quinidine), as these can dangerously increase Loperamide levels in your blood.
• Inform your doctor if taking other oral medications, as Loperamide slows gastric emptying and may affect their absorption.

Storage information:

• Store below 25°C to 30°C in a dry place.
• Protect the medication from direct light and moisture.
• Keep out of sight and reach of children.

Handling instructions:

• Swallow capsules or tablets whole with a glass of water.
• Drink oral rehydration solutions alongside this medication to replace lost fluids and electrolytes during diarrhoea.

Where is Loperamide available in Hong Kong?

In Hong Kong, Loperamide is classified as a Pharmacy Only Medicine. This means that while no prescription is needed, it must be purchased at a registered pharmacy under the direct supervision of a registered pharmacist.

You can legally obtain this medication at registered dispensaries displaying the "Rx" logo, as well as at pharmacy counters within general chain drug stores like Mannings and Watsons.