💊 Loperamide (Loperamide Hydrochloride)
Loperamide is an oral medicine used to control and relieve symptoms of acute nonspecific diarrhea and, in adults, chronic diarrhea associated with inflammatory bowel disease. Take only the dose set by your doctor or pharmacist: doses higher than recommended can cause serious heart rhythm problems and death. It must not be given to children under 2 years of age.
In Arabic: لوبيراميد (هيدروكلوريد اللوبيراميد)
✅ What it is used for
- Control and symptomatic relief of acute nonspecific diarrhea in patients 2 years of age and older
- Chronic diarrhea in adults associated with inflammatory bowel disease
- Reducing the volume of discharge from ileostomies (capsules)
🧪 Active ingredient
The active ingredient is loperamide hydrochloride, a synthetic antidiarrheal. It binds to opiate receptors in the gut wall, slowing intestinal motility and prolonging transit time, reducing daily stool volume, increasing stool viscosity and bulk density, and diminishing fluid and electrolyte loss. It also increases anal sphincter tone, reducing incontinence and urgency.
🌿 Benefits
- Reduces the frequency and volume of stools
- Reduces fluid and electrolyte loss through the bowel
- Clinical improvement is usually seen within 48 hours in acute diarrhea
- No tolerance to the antidiarrheal effect has been observed
📝 How to use
- Taken by mouth; the dose and duration are set by your doctor or pharmacist according to age and condition
- Do not exceed the maximum recommended dose, as higher doses increase the risk of serious cardiac reactions
- Fluid and electrolyte replacement should be given as needed during diarrhea
- Children 2 to 5 years (20 kg or less) should use the oral liquid rather than capsules
- Consult your doctor if chronic diarrhea does not improve after at least 10 days at the maximum dose
💊 Dosage forms
- 2 mg capsules
- Oral solution 1 mg/5 mL (used for younger children)
⚠️ Common side effects
- Constipation
- Dizziness
- Nausea
- Abdominal cramps
- Dry mouth
- Drowsiness
🚨 Serious — seek medical help
- Serious heart rhythm problems (QT prolongation, Torsades de Pointes, ventricular arrhythmias), cardiac arrest and death, especially at high doses
- Fainting (syncope)
- Severe allergic reactions including angioedema and anaphylactic shock
- Severe skin reactions such as Stevens-Johnson syndrome and toxic epidermal necrolysis
- Paralytic ileus and megacolon, including toxic megacolon
- Urinary retention
- Respiratory depression (especially in children under 2 years)
⛔ Do not use if
- Children less than 2 years of age
- Known hypersensitivity to loperamide or any excipient
- Abdominal pain without diarrhea
- Acute dysentery (blood in stools and high fever)
- Acute ulcerative colitis
- Bacterial enterocolitis caused by invasive organisms such as Salmonella, Shigella, and Campylobacter
- Pseudomembranous colitis (e.g., C. difficile) associated with broad-spectrum antibiotics
❗ Warnings & precautions
- Boxed warning: Torsades de Pointes, cardiac arrest, and death have been reported with higher than recommended doses, including abuse and misuse
- Avoid doses higher than recommended in adults and children 2 years and older
- Avoid with drugs or herbal products that prolong the QT interval, and in patients with congenital long QT syndrome, history of arrhythmia or cardiac conditions, or electrolyte abnormalities
- Diarrhea causes fluid and electrolyte depletion; loperamide does not replace appropriate fluid and electrolyte replacement
- Children may be more sensitive to CNS and respiratory effects; use with special caution
🔄 Drug interactions
- CYP3A4 inhibitors (e.g., itraconazole), CYP2C8 inhibitors (e.g., gemfibrozil) and P-glycoprotein inhibitors (e.g., quinidine, ritonavir) raise loperamide levels and may increase the risk of cardiac reactions
- QT-prolonging drugs: Class IA and III antiarrhythmics (quinidine, procainamide, amiodarone, sotalol), antipsychotics (chlorpromazine, haloperidol, thioridazine, ziprasidone), moxifloxacin, pentamidine, methadone and others
- Combining several enzyme inhibitors increases the risk further and calls for cardiac monitoring
- Tell your doctor or pharmacist about all medicines and herbal products you use
🤰 Pregnancy
There are no adequate and well-controlled studies in pregnant women (Pregnancy Category C). Animal studies showed no teratogenic activity, but very high doses impaired fertility and offspring growth and survival. Use during pregnancy only if the potential benefit justifies the potential risk to the fetus, after consulting your doctor.
🍼 Breastfeeding
Small amounts of loperamide may appear in human breast milk; therefore it is not recommended during breast-feeding.
🧒 Children
Contraindicated in children under 2 years because of the risk of respiratory depression and serious cardiac adverse reactions. For children 2 to 12 years the dose is weight-based and set by the doctor; children 2–5 years (20 kg or less) should use the oral liquid. Children may be more sensitive to CNS effects, and dehydration may increase variability of response. Safety and effectiveness in pediatric chronic diarrhea have not been established.
👴 Older adults
No dose adjustment is required in the elderly, but they may be more susceptible to effects on the QT interval. Avoid in elderly patients taking QT-prolonging drugs or with risk factors for Torsades de Pointes.
🌡️ Storage
Store at 20° to 25°C (68° to 77°F) in a well-closed container with a child-resistant closure, and keep out of the reach of children.
⏰ Missed dose
The label gives no specific missed-dose instructions. In acute diarrhea the drug is generally taken after each loose stool as directed by the doctor; never double a dose.
🆘 Overdose
Higher than recommended doses may cause life-threatening cardiac, CNS and respiratory reactions, including QT prolongation, arrhythmias, syncope, cardiac arrest and death. If overdose is suspected, contact a poison control center or go to the emergency department immediately.
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Mechanism of action
Loperamide binds gut-wall opiate receptors, inhibiting release of acetylcholine and prostaglandins, reducing propulsive peristalsis, prolonging intestinal transit time, and increasing anal sphincter tone. Apparent elimination half-life is 10.8 h (range 9.1–14.4); plasma protein binding about 95%; metabolized mainly by CYP2C8 and CYP3A4 and a P-glycoprotein substrate; excreted mainly in feces.
Labeled dosing
Acute diarrhea (adults and children ≥13 years): initial 4 mg, then 2 mg after each unformed stool; maximum 16 mg/day. Chronic diarrhea (adults): initial 4 mg, then 2 mg after each unformed stool until controlled, then reduce to individual needs (average maintenance 4–8 mg/day); maximum 16 mg/day; if no improvement after at least 10 days at 16 mg/day, symptoms are unlikely to be controlled. Children 2–12 years: weight-based first-day schedule (13–20 kg: 1 mg three times daily; 20–30 kg: 2 mg twice daily; >30 kg: 2 mg three times daily), then 1 mg/10 kg after each loose stool, not exceeding the first-day dose. The final dose is set by the doctor or pharmacist.
- Contraindicated in children under 2 years
- Provide fluid and electrolyte replacement as needed
- Avoid doses above recommended (boxed warning: Torsades de Pointes, cardiac arrest)
- Monitor for cardiac reactions with CYP3A4/CYP2C8/P-gp inhibitors
- Elderly: no dose adjustment, but avoid with QT-prolonging drugs
- Renal impairment: no pharmacokinetic data; no dose adjustment as excretion is mainly fecal
🎓 Key points for students
- Mechanism: gut opiate receptor binding, slowed propulsive peristalsis, longer transit time, increased anal sphincter tone
- Substrate of CYP2C8, CYP3A4 and P-gp; inhibitors raise exposure (itraconazole plus gemfibrozil increased exposure 12.6-fold)
- Most dangerous toxicity: QT prolongation and Torsades de Pointes at high doses or with misuse
- Contraindications: dysentery, acute ulcerative colitis, pseudomembranous colitis, children under 2 years
- Most common trial adverse effects: constipation (5.3% in chronic diarrhea) and dizziness
- Pregnancy: Category C
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What is loperamide used for?
It is used to control and relieve acute nonspecific diarrhea, chronic diarrhea in adults with inflammatory bowel disease, and to reduce ileostomy discharge volume.
Can I take more to stop diarrhea faster?
No. Doses higher than recommended can cause serious heart rhythm problems, cardiac arrest and death. Stick to the dose set by your doctor or pharmacist.
Can children take it?
It is contraindicated under 2 years of age. For older children the dose is set by the doctor based on age and weight, and the oral liquid is used for ages 2–5 years.
When should it not be used?
With bloody stools and high fever, acute ulcerative colitis, antibiotic-associated colitis, abdominal pain without diarrhea, or hypersensitivity to the drug.
Which drugs interact with loperamide?
CYP3A4, CYP2C8 and P-glycoprotein inhibitors such as itraconazole, gemfibrozil, quinidine and ritonavir, and QT-prolonging drugs. Tell your doctor about all your medicines.
Is it safe in pregnancy and breastfeeding?
There are no adequate studies in pregnant women, so it is used only if clearly needed after consulting your doctor. It is not recommended during breastfeeding as small amounts may pass into milk.
⚕️ For education only — not a substitute for advice from your doctor or pharmacist. Do not start or stop any medicine without advice. Source: official FDA drug label via openFDA (2025-10), simplified. Updated: 2026-11-11.