Yes, I took xanax once to come down from speed and ended up blacking out at work. I shot a longbow in the store and got sent home. Its amazing that I didn't get fired.
I used to think speed comedowns especially crystal meth ones were invincible until I tried liquid Haloperidol. Bye bye crash/high/tweakyness
To be clear for our viewers at home:
Tizanidine is the one like clonidine, and also marketed as a muscle relaxant. It's a central-acting alpha2 agonist, and the actual "downer" here. It will counteract the amphs to an extent, mainly some of the actual speedy stuff.
It wouldn't counteract the "rush" that lucky people get, since that's a whole different mechanism from the fast-pulse, sweaty, tooth grinding part that true artists enjoy.
I would NOT take it during your session, cause the speeding part is how most people know how much they've had and then you run into one drug wearing off sooner. If you took too much amphs, having the clonidine wear off first could throw you into adrenergic overload. That's the part that would kill you.
It's the same reason they warn, or used to warn, people about with beta blockers--unopposed alpha activation making your cardio systems explode.
And it could be why after a few days you found you couldn't "come down". For me, after 48 hours on meth, all I have to do to come down is close my eyes. That's why I don't even blink when I cross 96 hours. Or do I and it's just too fast for non-tweaker eyes?
I'd say around 8-12 hours to be sure, although I personally need a pretty hefty dose of tizanidine to feel much effect from it (cf. clonidine, doxazosin or even beta-blockers, which do a pretty good job for me even at low doses).
The dose was obviously hefty enough for you to blunt the effect of the amps.
You do realise that you're not likely to be relieved of any muscle spasms while using speed right? It's going to make them worse, as I think you're finding out. All taking the tizanidine is going to do is blunt much of what you want from the speed - you're not likely to find a way to overcome this conundrum I'm afraid.
So how long does tinazidine take to wear off? How long after taking it would I be able to use amps without it blocking the effects? I really overdid it the second day because I couldn't feel the speed while I was taking tinazidine, don't want to find myself in that situation again, it was kind of scary. Especially knowing that if the tinazidine wore off I could have stroked out.
The lesson? Loose arguments and win: A new friend, an enemy that now underestimates you, an understanding of their motivations and main points of argument (for later crushing and destroying every belief they ever held dear, if you so desired), a way into their lives if needed, to teach you more, the ability to make suggestions, offer guiding in ways they think it was all their idea. But even all that is mostly necessary, just the simple things you learn and dont miss every day are enough.