Recently had to stop taking Adderal and my neurologist put me on Guanfacine. He warned that it might make me tired and suggested I take it right before bed so that particular side effect would be mostly gone by morning. I'm only in my first week of taking it, and feel completely wiped out most of the day. Anyone have experience with this drug? I'm almost afraid to head out on a ride longer than 25 miles for fear I won't be able to complete it.