I took mine at 6 hrs. 6, 12 and 6. If you notice you are weak when you wake up, you should ask your doc for the timespan to take before bed. It's a time release version so it gives you coverage overnight. It is NOT for day use though, because they couldn't get the time release action to be real steady. It will give you coverage overnight, just not reliable enough for the daytime! It's also referred to as Mestinon 180.

I think you should talk to your doc about how they suggest you split this 3 dose Rx up. They must have had something in mind when prescribing it that way, based on their understanding of your symptoms.

Hope this helps.