Wing, Hi! Welcome to the forum.

You need to speak to your neurologist. You might be able to get Mestinon Syrup to have. That should not interfere with the colonoscopy prep at all! It didn't with mine. There are drugs people absolutely need to stay on before any procedure. Talk to the gastroenterologist's office about the tablets too, if you haven't already.

I'm no genius but the stomach is not located in the colon. You could be having issues with your stomach that are completely unrelated to the large intestines. No, I'm not saying not to have the colonoscopy!!! But you need to discuss ALL possibilities with a gastroenterologist.

A few examples of what can go wrong with the stomach/small intestines are H-Pylori (infection), celiac disease, gastritis (inflammation of the stomach), achlorhydria or hypochlorhydria (no or lack of stomach acid - which is very common after 40) and many other problems. There are some simple blood tests doctors can do to rule some things out.

The drug you're on gets rid of stomach acid. What if you don't have enough to begin with? I don't have any. An upper endoscopy is normally done to look at the stomach and small intestines.

And what if the problem is with your gall bladder or pancreas? A simple blood lipase level with liver enzymes too would check for a pancreatic enzyme issue.

I've had a colonoscopy, about a month after my MG crisis no less. I was fine. I had to stay there a bit longer so they could make sure I was okay. I was weaker due to the pain and anesthetic drugs but it did not tank my MG. It can, however, in some myasthenics and, like robocar said, you really need someone around during the procedure who knows about MG.

Is the colonoscopy being done in a hospital or clinic setting?

I think your docs need to really be sure about what is going on with you before more drugs are thrown at you. I hope the colonoscopy goes well and that you do get some answers soon. And I hope your MG does not get more than temporarily worse. Take care and keep asking questions!

Annie