Hi, Ravenclaw. Good to see you.

It helps to understand exactly what Mestinon does. And what MG does. You might already know this, but I'll put it out there anyway.

Acetylcholine (ACh) is the muscle gas that keeps everyone's muscles strong.

Acetylcholinesterase (AChE) is the enzyme that cleans up ACh when it's done with its job of making your muscles strong.

They both work together to make sure the body has a normal balance of ACh.

You're right that we have fewer muscle receptors for ACh to go into. Some does get in, even with severe damage to the receptors.

Mestinon blocks the AChE enzyme, so that we can use ACh for a "longer" period of time. If you consider two hours long! Mestinon is called a cholinesterase inhibitor.

Mestinon kicks in after about 1/2 hour and then wears off about 2-1/2 hours after taking it. So we get about two good hours of optimum ACh use.

And you are right that too much Mestinon can flood the neuromuscular junction, especially if there is a more severe destruction of muscle receptors.

There is no way to tell, though, how many muscle receptors you have. That is why using Mestinon can be tricky.

100 - 110 mg. is the amount most neuros say is the max for ONE dose. Some push that, but it can be dangerous. At that "tipping point," more won't do you any good.

Why? Because Mestinon keeps AChE from going in and cleaning up the excess amount. That's what can cause a cholinergic crisis. Whereas not enough ACh causes a myasthenic crisis.

ACh is also about supply and demand. The more you do, the more ACh you use up and, therefore, the more you need. So some doctors will say to take a larger dose (i.e., 80 instead of 60 mg.) while you run errands, etc.

The amount someone takes doesn't necessarily relate to the severity of the disease. In my case, for example, I can't take the other drugs (contraindicated) unless I crash. So I take 90 - 100 mg, every three hours around the clock. For me, a consistent dose is best. But that's me! Every dosing amount/spacing has to be tailored to each person.

And it can take a while to know what works for you. The frustrating part is that that dosing can change, depending upon what other drugs you're on, what your activity level is, how you metabolize drugs, etc.

Some people also have stomach upset with Mestinon. That's because you need acetylcholine to MAKE stomach acid! So too much of it for some people causes too much stomach acid. I don't have that problem because I don't have stomach acid.

And what can make it even more confusing is that the nightshade foods, to a lesser and variable degree, do what Mestinon does. That's why so many MG articles talk about avoiding nightshades.

Caffeine is a cholinesterase inhibitor, too. Have you noticed how they have more warnings lately about caffeine? That's because it can cause an overdose of ACh in people without MG.

I hope this all helps. MG is not an easy disease, nor are the treatment options. Doctors don't often have the time to lay all of this out for patients. They usually talk in more simple terms. They forget that we're all inquisitive and need to know this information.

Funny, Celeste. I like the gory details.

Annie

Don't make any changes in Mestinon dosing without speaking to your neuro first!