First, I am not an expert or Vet, but I am wondering if your dog has diabetes it could have been seizure brought on by ketoasidosis. I have a Bichon that has been diabetic for 3 years now and he has been on insulin 2x day. I looked up moderut and this is what I found:
This medication contains two diuretics (amiloride and hydrochlorothiazide) that are used to decrease certain cases of edema (fluid retention) that occur with congestive heart failure and disorders of the liver. It is also used to lower high blood pressure. This medication works by causing the body to lose excess water and salt. One of the diuretics, amiloride, called a potassium-sparing diuretic, does not cause potassium to be lost from the body, while the other, hydrochlothiazide, does cause potassium to be lost from the body.
Did the vets check blood glucose levels? The symtoms you are describing is exactly what was happening with my dog when I found out he was diabetic. He has been on insulin ever since, goes in for regular blood glucose curves, and has been regulated since. I would explore it more with your vet or another one.
Oh, one more thing, when my dog was first diagnosed, I was afraid to do the insulin shots and asked the vet about pills.They had told me that they are successful somewhat with the pills for cats, but a high percentage doesn't work with dogs. Most dogs have the insulin dependant diabetes. Perhaps this is the case. Here is a good site for you if you want to talk to other diabetic dog owners:
http://www.caninediabetes.org/