that's one reason I hated Neurontin -- the water retention was terrible, plus the loopiness really got to me. I just couldn't tolerate all the water!
My doctor switched me to Topamax, as I didn't retain ANY water -- plus I LOST about 10 lbs on it, which is common on Topamax.

You normally don't retain water on it. There is normally no "loopiness" either. There can be some side effects, but I didn't have any. I'm still taking it.
You might want to ask your doc if you can switch to it. As far as I'm concerned it's a much better drug. I feel it works better than neurontin too, as far as the pain is concerned. Best of luck & God bless. Hugs, Lee