Not gonna make a habit of doing that, but one 12.5 keeps me asleep for a mere 4.5 hours out of 7 hours. I was just wondering if i had a big day the next day, and needed about 8 hours of rest, would (2) 12.5 mg of Ambien CR work.. or would i overdose?? Plus whats the next Rx a doctor prescribe you if Cr doesn't work?