I take Gabapentin 3x daily, so up to 900 mg per day. I've been on it since January of this year. All I notice is feeling a little groggy, so I take it in the afternoon, rather than first thing in the morning (which is the time when I feel most exhausted and have some driving to do). Then, I take the other 2 doses in the evening. It isn't enough to make me go to sleep, and it isn't enough to make such a huge difference with the anxiety. However, I find that I'm not taking as many benzos as I was, so maybe it's making more of a difference than I thought. I hate the grogginess though, especially since my current cocktail is kind of what you would give someone, if you want them to space out and act dopey all day.