narutokun said:
Well I IVed about 80mg methylphenidate and I noticed that both my hands have been tingling and I have this tingling and numbing at the same time feeling in my hands... This hasn't happened before

. Does anyone know what can this be? Detailed "biological" (generalizing) explanations are always welcome.
Sounds like you could have missed a little bit. I know when I used to IV heroin, if I missed a shot, on occasion it would leave the whole arm that I shot up in numb and tingling. On even more rare occasions, and this probably has nothing to do with what your asking, but ill share anyway, if the shot was still hot when I would miss it, it would leave a burn around the area where I missed, like something similar to if you spilled hot water on your skin, it bubbled up like a huge blister, obviously from the hot water being under the skin, and it would leave my entire arm numb also. Rather nasty.
Also, for some odd reason I could never understand, it would make the hand on that arm swell up to probably a quarter times its normal size and turn a dark purple color with white little blotches spread around the purple area, real freaky shit.
If I ever for some reason start to IV heroin again and it happens, Ill be sure to remember to take a picture so you can see what I mean, its rather disgusting.
Anyways, could be you missed some. Its not always as obvious because it doesnt always leave a lump. If you get it in the muscle, you wont see a bulge as you would if you got it under the skin.