Dumb question from me.. how old is that mestinon? if it is old, then it won't work. I have had MG for over 18 years and I hate to admit that my double vision never went away. I was in remission for 17 years but still had the double vision. I know many will say then you weren't in remission but according to my Dr I was and I had no weakness anywhere else {until this past Nov when MG reared it's ugly head again} Talk to your Dr and see what he/she says, they have come a long way with meds and MG.