So what symptoms do you have without meds, and do any of them improve with meds. If not then clearly something is not right. Maybe a different medication is needed.

I see from earlier posts that you were on prednisone, IGIVs and Cellcept.

That being the case, I would be surprised if a single Mestinon tablet could make that much difference, BUT it could perhaps be an interaction with one of the other drugs.

I 2008 T tested positive for the AChR antibodies and treated accordingly.
After 2 1/2 years I was told I was stabilized because my symptoms were not as terrifying, (less severe and less frequent) and stated experiencing things that were not normal for one with MG.
1 example. I would feel pretty god in the morning and maybe run some chores. Instead of feeling less fatigued I felt even better later in the day. It's a long story how I ended up with this Neurologist but in mid 2013 my blood work came back seronegative and he slowed my treatment to 0. He refused to send me for a SFEMG fearing it could come back seropositive. I knew I was still inflictive and 3 other refused to send me for a SFEMG.
After an incident, I went to a Neurologist in Cal. that sent me to UCLA for a SFEMG but the blood work preceded me and I was positive again. That UCLA Dr. prescribed Cellcept and Mestinon with a referral to a Neurologist back home. The first Mestinon worsened my condition.
When I was being treated I was taking 5 60 mg. a day. Strange, but new Neurologist next week might have some answers. Thank you for your reply.

Let me state, that I am not a doctor, and I can only make suggestions from extensive reading, of what other people have experienced.

That said, it does sound as though you MIGHT have one of the CMS variants or some other Myasthenic syndrome. It is certainly possible that you might have MG too.

Obviously if your root problem is partly or wholly not an auto-immune disease (CMS are genetic defects) then taking immuno suppressants could cause all sorts of new problems.

I hope that your new Neuro takes a serious look at all of your history and gets to the bottom of the problem. Fingers crossed.

Thank you again for your response. I see him on the 27th.

Please what ever you do DO NOT let him or her rush you untill YOU feel all your questions and concerns are answered. I've had a couple docs come in and ask few questions and slam bam thank you maam and out the door before I could ask THEM questions.

Juliejayne and jvaagen: Thank you very much for your responses.
The new Neurologist seems interested in helping me and set up my first IGIV for tomorrow. Maybe because he really respects the DR. from UCLA that referred me to him.
jvaagen: if anyone did not take the proper time it was me. There were questions I wanted to ask but did not make notes first.
Most importantly, I seem to be the only person with a positive diagnosis of MG that has had a negative effect from Mestinon.
I know there some people with MG that do not respond in a positive way to Mestinon but never a negative response.
Especially 1 single 60 mg tablet on 3 separate occasions over a 6 day period.
scrubbs