I take Clonidine for my high blood pressure. I am currently on 3.0 (yes, 3.0)mg per day, although I usually don't take the mid-day dose most days. I've been on clonidine for decades and it still makes me sleepy shortly after I take one. I've never heard it being used as a sleep aid, because it does have pretty strong effects on lowering your BP. I don't think clonidine has a long "build up" period. It kicks in on me after about 15 to 30 minutes. I have terrible problems with sleep, but I don't think it's related to that med. For me, it is the most important med I take each day, including psych meds. I would have probably had a heart attack or stroke without it. Monitor your pressure carefully at several points throughout the day. You can get a BP monitor for not too much these days, and it may come in handy. Please be careful driving or anything, because it can definitely dull your senses.