Loperamide — NZ Medication Guide
📋 Reviewed by a Registered Pharmacist NZ — This information is for general educational purposes only and does not replace professional medical advice. Always consult your doctor or pharmacist before starting, stopping, or changing any medication.
What is Loperamide?
Loperamide is a peripheral opioid receptor agonist used as an antidiarrhoeal medicine. This medication is commonly prescribed in New Zealand and is available over-the-counter and funded by Pharmac in certain circumstances.
What is Loperamide Used For?
Loperamide is used for the symptomatic treatment of acute diarrhoea (e.g., traveller’s diarrhoea, non-specific gastroenteritis) and chronic diarrhoea associated with conditions such as irritable bowel syndrome (IBS) or inflammatory bowel disease.
How Does Loperamide Work?
Loperamide acts on mu-opioid receptors in the enteric nervous system of the gut, reducing intestinal motility (slowing bowel transit), decreasing intestinal secretions, and increasing anal sphincter tone. Unlike systemic opioids, it does not cross the blood-brain barrier significantly, so it does not produce central opioid effects at normal doses.
How to Take Loperamide
For acute diarrhoea: 4 mg (2 capsules) initially, then 2 mg after each loose stool. Maximum 16 mg/day. For chronic diarrhoea: 4–8 mg/day in divided doses, adjusted to response. Do not use for more than 48 hours in acute diarrhoea without medical review.
Common Side Effects of Loperamide
- Constipation (dose-related)
- Abdominal cramps
- Bloating
- Nausea
- Dizziness
Serious Side Effects — Seek Medical Attention
Contact your doctor or call 111 immediately if you experience any of the following:
- Toxic megacolon (in inflammatory bowel disease — do not use if this is suspected)
- QT prolongation and cardiac arrhythmia (at high or excessive doses)
- Paralytic ileus
Drug Interactions
Loperamide may interact with other medicines. Always inform your doctor and pharmacist of all medications, supplements, and herbal products you are taking. Key interactions include:
- P-glycoprotein inhibitors (quinidine, ritonavir — increase loperamide levels and risk of cardiac effects)
- Other opioids (not recommended to combine)
New Zealand Prescribing Information
Loperamide 2 mg capsules (Imodium® and generics) are available over-the-counter at New Zealand pharmacies without a prescription for acute diarrhoea. Funded prescriptions are available for conditions such as chronic diarrhoea associated with IBS, ileostomy, or IBD. Do not use loperamide if you have bloody diarrhoea or a high fever without first consulting a doctor, as these may indicate an infectious cause requiring antibiotics.
Frequently Asked Questions
Can I give loperamide to children?
Loperamide is generally not recommended for children under 12 years without medical advice. In young children, diarrhoea management should focus on oral rehydration therapy (ORT) rather than antidiarrhoeal medicines. Always consult your pharmacist or doctor before giving any medicine to children.
Can I use loperamide if I have IBS?
Yes — loperamide is often used for IBS-D (IBS with predominant diarrhoea) to manage urgent and loose stools. It does not address the underlying cause of IBS and should be used as part of a broader management plan. Discuss appropriate use with your doctor or pharmacist.
⚠️ Disclaimer: This page is for educational purposes only. It is not a substitute for professional medical advice, diagnosis, or treatment. Always seek the advice of your doctor or a qualified health provider with any questions you may have regarding a medical condition or medication. In New Zealand, medication availability and funding may vary — check with Pharmac or your pharmacist for the most current information.
Reviewed by a Registered Pharmacist NZ
References & Further Information
The following New Zealand and international resources were used to inform this page: