Imodium for Dogs: Is it a Good Idea?

When faced with a case of upset tummy (read: diarrhea) in your dog, it’s natural to wonder if you really need to make a trip to the veterinary office or if you can treat your dog at home with something like Imodium. Let’s take a look at when it is okay to give your dog Imodium, and more importantly, when it is not.

What is Imodium?

Imodium (generically known as loperamide) is a synthetic opioid. All opioids (think morphine, oxycodone, etc.) have a well-earned reputation for causing constipation. Loperamide is so good at causing constipation that this “side effect” has become the primary reason we use it as a medication. On the other hand, Imodium is not very good at relieving pain, at least at safe dosage levels, so it is never legitimately used for this reason.

Is Imodium Safe for Dogs?

Some dogs with certain types of diarrhea can take Imodium, but in other cases, giving your dog Immodium can lead to potentially serious side effects like constipation, sedation (which can be severe), bloat and pancreatitis. Here are several instances when you should NOT give your dog Imodium:

1. Your dog is a herding breed (like a Collie, Sheltie or Australian shepherds). These dogs may carry a mutant form of the ABCB1-1Δ (MDR1) gene that dramatically limits their ability to break down some types of drugs, including Imodium. Dogs can be tested for the MDR1 gene, but unless you are sure of your dog’s status, abide by the veterinary adage, “White Feet = Don’t Treat.”
2. Your dog’s diarrhea could potentially be caused by an infection (e.g. Clostridium perfringens bacteria) or toxins like those found in some types of poisonous mushrooms. Diarrhea is the body’s way of flushing out these offenders, so the last thing you want to do is eliminate that process.
3. Your dog has another health condition (e.g. liver or kidney disease, Addison’s disease, difficulty breathing, hypothyroidism, or a head injury) that could make them more susceptible to the side effects of Imodium. Also avoid Imodium if your dog has abdominal pain, is vomiting profusely, is very old or very young, or is significantly debilitated in any way.

If none of these conditions are relevant to your pet’s situation, call your veterinarian to see if he or she thinks giving your dog Imodium is a good idea. Your vet may recommend a different dose (or different treatment altogether), but something along the lines of 0.1 mg/kg of Imodium given twice a day is typical. If you do the math, this means that a ten-pound dog might receive a dose of 0.4 mg of Imodium while a dog who weighs 50 pounds could be given around 2 mg. Imodium tablets contain 2 mg of the drug and should only be given to larger dogs. Liquid Imodium is typically available in a concentration of 1 mg/5 mL (0.2 mg/mL), so is a better choice for smaller dogs.

Always confirm the correct dose of Imodium with your veterinarian since it may be adjusted based on your dog’s unique situation. If you are wary of giving your dog Imodium, other at-home options to treat mild dog diarrhea include probiotic supplements, dietary therapy, kaolin/pectin products, or Pepto-Bismol. Imodium should never be given to cats except under close veterinary supervision. Cats are extremely sensitive to this drug and are likely to develop agitation and excitatory behavior.

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