I took a low dose (25 mg because I am sensitive to drugs) for approximately 4 years due to working different shifts and it worked beautifully with no side effects until it stopped working-at any dose. Seemingly overnight I could no longer sleep on my own and I suffered from horrible insomnia, anxiety (which I had never had before) and depression. As with any drug, it can stop working and leave you in a worse place before you started. I tried it again several years later at 75 mg but it caused severe dry mouth and a very stuffy nose which I couldn’t tolerate. Wish I had never started a sleep medicine to begin with.