"i have taken ambien cr on a nightly basis for nearly two years now and have found that it is truly helpful. i have found that after a year or so on a 6.25 mg dosage i had to go up to 12.5 mg in order to achieve the same result. other than developing a tolerance to it however, i have found that ambien cr is extremely effective. i am able to fall asleep easily and my sleep is a very peaceful one that leaves me feeling well rested in the morning."