Hi there. Yes, you can give dogs imodium for diarrhea. The dosage is 0.02-0.1 mg/lb, so if you give a dosage in the middle of this range then that should be ok, the higher end dosages can cause constipation. The dose can be repeated every 8-12 hours.
It is fine to use in dogs that are bright and well, but have diarrhea. If your dog is ill in herself, then you shouldn't use it.
It would be 0.1-0.2ml per 10lb bodyweight if it's the 0.2mg/ml syrup that you have.
You are fine to try it with the symptoms that she has.
I really hope it helps!