If I take two 5 mg of zolpidem nightly, I wake 4 hours later and am clear headed and wide away. I can not go back to sleep. Why can't I take one 5 mg when I go to bed and take the other 5 mg when I awake to extend my night sleeping past 4 hours? The price of zolpidem CR slow release tablet helps you fall asleep but then keeps you asleep longer than 4 hours. The price of zolpidem CR is 10 times the cost of the regular zolpidem.