Lets 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 ...