loperamide hydrochloride at a glance
Medicine class
Antimotility antidiarrhoeal acting mainly within the gut.
Main role
Symptomatic relief of acute diarrhoea; selected products also cover doctor-diagnosed IBS diarrhoea or chronic diarrhoea.
Administration
Standard tablets and capsules are swallowed with water; orodispersible tablets dissolve on the tongue without water.
Hydration
Replacing fluid and electrolytes remains important because loperamide only controls symptoms.
What is loperamide hydrochloride used for?
Licensing varies between products. Selected UK products cover:
Symptomatic treatment of acute diarrhoea.
Acute episodes of diarrhoea associated with IBS in adults whose IBS has already been diagnosed by a doctor.
Some prescription tablet products: acute exacerbations of chronic diarrhoea in adults and eligible children, and chronic diarrhoea in adults.
How does loperamide hydrochloride work?
Loperamide activates opioid receptors in the bowel wall. This reduces propulsive contractions, lengthens intestinal transit and allows more water and electrolytes to be absorbed, producing firmer stools and less urgency. Very little unchanged loperamide normally reaches the circulation because of extensive first-pass metabolism.
loperamide hydrochloride preparations and strengths
Capsule
Route: Oral
Strengths: 2 mg
Dispersible tablet
Route: Oral
Strengths: 2 mg
Tablet
Route: Oral
Strengths: 2 mg
How to take loperamide hydrochloride
Follow the instructions supplied with the product or those given by the prescriber. Keep drinking suitable fluids because controlling diarrhoea does not prevent dehydration.
It may be taken with or without food.
Swallow standard tablets or capsules whole with water.
Place an orodispersible tablet on the tongue, allow it to disperse and swallow it with saliva; water is not required.
Do not chew an orodispersible tablet.
loperamide hydrochloride side effects
Common or expected effects
- Constipation
- Nausea
- Flatulence
- Headache
Get urgent medical advice
- Severe constipation, ileus or marked abdominal swelling
- Serious allergic reaction, including facial or throat swelling and breathing difficulty
- Fainting, reduced consciousness or severe loss of coordination
- Severe blistering or peeling skin reaction
- Severe abdominal pain with vomiting or fever, which may indicate pancreatitis
- Fast or irregular heartbeat, particularly following excessive use
loperamide hydrochloride in pregnancy
Loperamide is not usually recommended during pregnancy because human safety information remains limited. Non-drug measures and the cause of diarrhoea should be considered first; use should be discussed with a doctor when symptoms are persistent or treatment is considered necessary.
loperamide hydrochloride while breastfeeding
NHS patient guidance considers loperamide compatible with breastfeeding because transfer into milk is small and infant absorption is limited. Selected product information is more cautious and states that it is not recommended; a pharmacist or prescriber can reconcile this when regular use is contemplated. Seek advice if the infant feeds poorly, becomes constipated or seems unusually irritable.
loperamide hydrochloride interactions
Check concurrent medicines with a pharmacist or prescriber, particularly those affecting loperamide metabolism or bowel motility.
Quinidine or ritonavir
P-glycoprotein inhibition can increase loperamide exposure; the clinical importance at licensed use is uncertain.
Itraconazole or ketoconazole
CYP3A4 and P-glycoprotein inhibition can substantially increase loperamide concentrations.
Gemfibrozil
CYP2C8 inhibition increases loperamide exposure, especially when combined with itraconazole.
Oral desmopressin
Common questions about loperamide hydrochloride
Answers are fully visible for fast scanning and source review.
Does loperamide hydrochloride cure the cause of diarrhoea?
No. It reduces bowel movement and improves stool consistency but does not treat infection, inflammation or another underlying cause.
Can loperamide hydrochloride be used when there is blood in the stool and fever?
No. This pattern may indicate dysentery or invasive infection and requires medical assessment rather than routine antimotility treatment.
Sources
These sources were used to prepare and review this medicine page.
Prepared and reviewed by the iatroX editorial team.