"i just made the switch from ambien to lunesta because ambien just wasn&#039;t working for me anymore. i am not a regular taker, just on the odd occasion like traveling. but i took lunesta for the first time last night and i did fall asleep quickly but after about four hours i suddenly awoke. then woke up again after another four hours wide awake! this was at 5 in the morning and i wasn&#039;t ready to get up. i guess that is kind of a good thing because i didn&#039;t feel groggy or sleepy at all. i lay there and finally drifted off for a couple more hours and then i had a weird dream. the metallic taste is the only side effect i have noticed. "