From practical experience, not so odd.
Not however, with guanfacine, sadly they don't use it in the UK, asked my doc about it, as at some dosages apparently it has nootropic potential.
Tizandine I get on script, and I have had clonidine before, orally, sedating, will lower heart rate/BP, damn good opiate potentiator, actually, for some reason it seems to improve most drugs, at least in my opinion. Take too much, and it will put you flat on your back, out cold, or produce a state that could perhaps be compared in appearance, to an opiate nod, minus the euphoria, relaxing yes, sedating-very, but not actually euphoric.
Stick the stuff where the sun don't shine, and its another matter entirely, I have adjusted to it somewhat, after being scripted it quite a while (I'm autistic, use the stuff to kill off any unwanted sensory input-related overload annoyance, works perfectly) but 4mg that way would cause pronounced ptosis of the eyelids, sudden uncontrollable half-sleep, etc.
A little more, (and still) it would knock me out cold within about 10-15 minutes, I have used it pluged, on desoxypipradrol, whilst still fully under the effects of it and it still managed to KO me.
Lower doses though, I find work very well to focus attention, my attention span is all over the damn place, I suspect, perhaps, I may have at least some ADD-ish tendencies, in fact thats about the only reason I ever use stimulants.
A2 adrenoreceptor agonists are certainly anything but stimulating though.
Different drugs of this class tend to have different levels of effect on blood pressure, tizanidine IIRC is something like 40x less potent as a hypotensive agent than is clonidine. Clonidine has in the past, without producing strong sedation like tizanidine would, made me more or less unable to move, whilst laid out on my back on a bed.
Couldn't get up, could barely reach over a few feet to spark a fag.
Pretty much all of the A2 agonists are based on an imidazoline ring structure, and there exists an imidazoline receptor (with several subtypes, one of which is located in the medulla oblongata, near the brain stem which controls autonomic function) And most of them hit both A2 adrenoreceptors and the imidazoline-1 receptor.