Loperamide, often sold as Imodium, is a fast way to stop sudden diarrhea. It slows gut movement so stools firm up and you make fewer trips to the bathroom. That makes it handy for short bouts of diarrhea and traveler's diarrhea when you don’t have a fever or bloody stools.
For adults the usual over-the-counter dose is 4 mg (two 2 mg tablets) at first, then 2 mg after each loose stool. Most OTC guidelines cap the dose at 8 mg per day. Prescription plans may allow higher doses for certain chronic conditions, but don’t raise the dose without your doctor. For kids, dosing depends on age and weight—check the product label or ask a pediatrician. Never give loperamide to infants without medical advice.
Use loperamide for short-term relief. If diarrhea stops, don’t keep taking it. Also pair it with oral rehydration fluids if you’ve lost a lot of water—especially in hot weather or if you’ve been vomiting.
Loperamide is safe when used correctly, but it can be dangerous if misused. Taking very large amounts can affect the heart and cause life-threatening irregular rhythms. People have misused it to try to reduce opioid withdrawal—don’t do this. If you take strong inhibitors of CYP3A4 or CYP2C8 (some antibiotics, antivirals), loperamide levels can rise and increase risk of heart issues.
Don’t use loperamide if you have bloody diarrhea, a high fever, or signs of bacterial infection like severe abdominal pain. Also avoid it if you suspect C. difficile infection—slowing the gut can make that worse. If you’re pregnant or breastfeeding, talk to your healthcare provider before using it.
Common side effects are mild: constipation, abdominal cramps, and dizziness. Stop and seek help if you get a fast or irregular heartbeat, fainting, severe belly pain, or if diarrhea lasts more than 48 hours despite treatment.
Store loperamide at room temperature away from moisture and heat. Keep out of reach of children. If you ever find yourself tempted to take more than recommended, call your doctor or poison control instead.
Want to treat traveler's diarrhea? Loperamide can help symptoms, but if you have fever or bloody stools, get medical care—antibiotics may be needed. For routine cases, follow the dosing above, stay hydrated, and watch for warning signs. When in doubt, ask a pharmacist or clinician; they’ll help you pick the right option without risking your heart or masking a serious infection.
