PupkeeperToxic
Dog ate loperamide (diarrhea pills)? What to do
Toxic. Loperamide (Imodium) can make dogs very sleepy, wobbly and drooly, and collies, shelties and other MDR1 dogs can be poisoned by a normal dose.
If your dog ate or touched this, call your vet or a pet poison line now
United States
Poison lines in other countries: United Kingdom, Australia, Canada, New Zealand
What to do now
- Call your vet or a pet poison line now.
- Keep the packaging and bring it with you.
- Tell the vet your dog's breed, especially a collie, sheltie, Australian shepherd or other herding breed or mix.
Don't
- Don't give loperamide unless your vet tells you to.
- Don't make your dog vomit unless a vet tells you to.
Signs to watch for
- Sleepiness or depression
- Vomiting
- Heavy drooling
- Wobbly walking
- Weak back legs
- Belly pain
- Restlessness or crying out
- Low body temperature
When signs appear: Within 30 minutes to 6 hours
Why
Dogs with the MDR1 (ABCB1) gene change, found in collies, Shetland sheepdogs, Australian shepherds, Old English sheepdogs, longhaired whippets, some German shepherds and their mixes, let this drug into the brain, so even a normal dose can cause nerve signs.
Sources
- Geyer and Janko, Curr Pharm Biotechnol (2012): Treatment of MDR1 Mutant Dogs with Macrocyclic Lactones
- Vet Times: Loperamide, a Human Medication Toxic to Pets
Guide reviewed 9 October 2026.
General information from the sources above, not a diagnosis. When in doubt, call your vet.