I have Seroquel on hand (which I already take a low dose of) as a PRN for hypo/mania. I haven't had to use it for a couple of years, but in the past, if I took enough, it brought me crashing down, like sucking all of the air out of a crazy-making, out of control balloon.

I strongly suggest, too, having a PRN for episodes. I do believe that, in some cases, it can prevent IP or at least things getting too out of control. I'd talk with one's pdoc first, though, about how much to take, to keep it both safe and effective.