insomnia
"I just made the switch from Ambien to Lunesta because Ambien just wasn'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't ready to get up. I guess that is kind of a good thing because I didn'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. "