I have similar reactions to taking too much Mestinon, the muscle twitches and not being able to sleep very long as well as nervousness. These effects were really bad when I was taking 60 mg at a time, but it still happens sometimes when I take 30 mg at a time.

I was taking 30 mg of Mestinon 3 times per day (4 hours between and none at night) and it was working great for me for quite some time, about 6 months I think.

Recently I haven't been able to take so much and the amount I need has been varying greatly, I don't understand why but I am generally feeling better so that is good. Now, some days I need 30 mg per day and others I need 90 mg per day. On good days I am taking 15 mg per dose.

I am waiting until I feel the beginnings of weakness before taking Mestinon. I wish I could take more Mestinon to prevent these weak times, but the symptoms from too much Mestinon are scary for me. Recently, when I took "too much" Mestinon I was getting a rapid heartbeat and general nervousness. Also, it made me breath fast and shallow. Taking less Mestinon resolved these issues.

One more thing, when I get these twitches and other symptoms from too much Mestinon my muscles don't work properly, but the weakness feels different that from not enough Mestinon. I can't figure out how to describe it. I will try. With too much Mestinon, my muscles feel like they are vibrating and tense and they don't exactly feel weak but when I try to use them they don't function properly. With not enough Mestinon my muscles FEEL heavy and weak. Either way, the muscles are weak even if the feeling is different from too much vs. not enough Mestinon.

I hope this information helps.