Please note:there seems to be confusion about the drug PROStIGMIN and the drug PYRIDOSTIGMINE which is the same drug as Mestinon which most of us take today. Prostigmin is an old drug which was used 30 years ago or more - it is NOT Pyridostigmine . It has a shorter duration of action than Mestinon and a lot more GI side effects. We had no choice 40 years ago as this was the only drug we were given. Mestinon is a smoother drug and has less side effects. Prostigmin is not used as much in modern neurology today and this might be why it is being discontinued . We have an arsenal of drugs today that didn't exist years ago. Prednisone and Prostigmin were our only choices - today we have choices including immunosuppressants , IVIG, Plex and certain chemo drugs. If it becomes unavailable you have other choices and you will do well.