shift work sleep disorde
"This medicine does a great job! I thought "wow" I've finally found something to help me make it through the night without side effects. Almost. On my second prescription I developed scattered hives. My Dr. Said take an antihistamine and try again, since it hadn't done this before. I thought that might work until I got hives in more and more places each time I took it (I only take it when needed). 
When I developed the hives in very personal places that's when I decided I have no choice but to not take it. I don't know why it took so long to cause an allergic reaction. I wish it didn't because it really does work great. I'm hoping to find something else that does same thing that I'm not allergic to."