"for many years, i had no problems falling asleep but after 4 hours would wake again, wide awake, mind racing, etc. i finally asked my doctor to prescribe ambien and paid extra to get it. it was worth every penny. i found a whole tablet taken at bedtime still only let me sleep 4-5 hours. i had been told i might need to take another tablet if i woke too early, but didn&#039;t want to do that. so now, i don&#039;t take ambien at night when i go to sleep. i take 1/2 of a 5 mg tablet when i wake up at 2 or 3 a.m. it works like a charm; i sleep another three or four hours. for me, 2.5 mg works just as well as 5 mg. great sleep and i&#039;ve never had sleep amnesia."