Imodium can be helpful for dogs with diarrhea, but some can be unsuitable for treatment depending on their breed, medical conditions and other medicines they are taking. The following information should help you to determine whether Imodium (loperamide) is right for your dog.


There are several contraindications for the use of Imodium, and several unsuitable breeds:

MDR1 gene mutation

Dogs with an MDR1 gene mutation could suffer side effects as a result of Imodium use. The breeds most commonly associated with this problem are:

  • Australian and German Shepherds
  • Collie dogs
  • English, McNab, Old English and Shetland Sheepdogs
  • Longhaired whippets
  • Silken Windhounds
  • Skye Terriers

Mixed breed dogs could also be affected and concerned owners may wish to have their pet tested for the gene.


Tell the vet if your dog suffers from enterocolitis, dysentry, colitis or abdominal pain without diarrhea. Use is not recommended in pregnant/nursing dogs, or young puppies under 6 weeks of age.

Never give Imodium to dogs who are suffering from diarrhea as a result of ingesting a toxin as this will inhibit its removal from the body.

Drug Interactions

Mixing loperamide with the following drugs could be dangerous:

Alprazolam, amitraz, amitriptyline, butalbital, diazepam, fluphenazine, furazolidone, lorazepam, naloxone, nortriptyline, perphenazine, phenobarbital, quinidine, ritonavir, selegiline.

It may also interact with any other barbiturates, benzodiazepines, phenothiazines and tricyclic antidepressants.

I Just Gave Imodium To An Unsuitable Dog!

The side effects of Imodium are typically mild, however, if you have any reason to believe you have given this medicine to a dog who’s unsuitable for treatment you should call the vet for advice. If your pet suffers any serious reactions call for emergency help, this includes cases of allergic response.