You wrote:

Nope, that's not it either.

Talking about a half-life of a drug is deceptive. Jump in here anytime, Mrs. D.

Mestinon COMPLETELY wears off by four hours. For me, it's done working at the 2-1/2 hour point - that is, 2-1/2 hours after I take it. At that point, my body needs more but I have only been "approved" by my neuro to take it every three hours. And that is EVERY THREE hours, round the clock. Or 8 doses in one, 24-hour day. Theoretically, I suppose some people - like those who are hypothyroid and have a slower metabolic rate - could have Mestinon in their body longer than four hours. But for most people, it's gone in at least 4 hours.

Yes, the strength of Mestinon does vary within that "four hour period." It is not a constant strength. That is why some patients with MG are on Mestinon every three hours or 2-1/2 hours or 2 hours. Again, you can't decide that on your own, it has to be a decision between your and your neuro.

And this makes it even more interesting. If your body needs more acetylcholine, like when it's doing something, it can "use up" that Mestinon even faster. That's why you can get weaker the more you do things. It's a "supply and demand" issue.

I don't know where you are getting the information about Mestinon but I hope others aren't getting the same. When in doubt, contact the drug manufacturer: Valeant Pharmaceuticals. Or hope that your pharmacist knows about it and ask them.

Forget about "half-life" of drugs. Think about the full life of them. The full life of Mestinon is FOUR HOURS. Within that period of time, how strong it is or when it kicks in or wears off is different for people.

With people who are just starting Mestinon, doctors will not often allow them to take it more than every four hours or three or four times a day. They want to see how they do on the drug before they up the dose amount (the number of milligrams) or the dose frequency (how many hours in between they take it). Because it is easy for someone who isn't used to a disease or drug to understand all the parameters and how it works for them, it can be easy for them to overdose. That is called a "cholinergic crisis." That's when you get too much acetylcholine.

When you get too little acetylcholine (to clarify, too little to the muscle), it's called a "myasthenic crisis," because it's not the drug causing the weakness but the disease. Make sense?

That's why the dose Kasper's doc was giving her, the 60/90/60/90 was kind of crazy. Then it's hard to tell when you are getting too much or not enough of a drug.

And to confuse you even more, recent studies show that while the drug Mestinon may wear off within four hours (or less), it's effects can last up to two weeks or more. The effects I'm talking about are not how Mestinon gives you more acetylcholine for four hours. It's the effects on the immune system that seem to last longer. They believe Mestinon actually has a suppressing effect on the humoral immune system that produces antibodies. Not enough studies have been done on this, however, to "prove" that.

There is a natural "checks and balances" system in the body with regards to acetylcholine (ah-seat-ill-co-lean). Normally, the body produces acetylcholine, uses it in the neuromuscular junction and then the little "PacMen" enzyme called acetylcholinesterase (ah-seat-ill-co-linn-ess-ter-ase) comes and eats up the "used" acetylcholine. Since people with MG don't have enough acetylcholine (getting to the muscle), we need Mestinon to "fend off" the enzyme so we can use the acetylcholine longer. Kind of like how there are long lines while you wait to buy a popular movie or book (if you go to a store, instead of on-line). It takes a while for all the acetylcholine waiting in line to help your muscles because there aren't as many "receptor cashiers" to receive it. BTW, my "sounds like" of those words are not dictionary accurate but how they sound when you say them.

Extremes of heat and cold (well, actually, not that extreme), will increase the workings of that little enzyme that eats up acetylcholine. That will overwhelm the acetylcholine and you simply get weaker, no matter how much of it you've taken. I dread the summer months because of that. If you are bad off going into hot weather, you have to be VERY careful not to overheat.

If you have more questions of anyone here, please ask. This is a lot to take in and understand. Not to mention the other issues of drug interactions, relatively contraindicated drugs, what triggers MG to be worse, etc.

I hope this helps. I think a conversation with your neuro is in order too!

Annie

Sorry about the length, guys. I tried to break up paragraphs as much as possible.