I have been on celexa 30 mg for about 2 years and klonopin 0.75 mg for about 2 years as well taken at night for insomnia. I take the klonopin for insomnia. I am switching to Lexapro in hope of it allievating the anxiety, depression, and klonopin. My doctor is switching me straight from Celexa to Lexapro no weening off as he said they are in the same class. Today has been my first day on 15 mg of Lexapro and I have a major headache and am so drowsy and out of it. How long until this goes away? I am scared that I am going to be continuously drowsy and tired. Additionally what time of the day is best for the Lexapro? Has anyone gotten good results of feeling great and energised during the day from this drug and also having this drug getting rid of their insomnia, or sleeping well throughout the night? Thanks so much!