Hi, thanks for your comments in advance:

I have taken Adderall 20mg before, twice a day with much success, but I decided to stop taking it after about a month and a half to see if I could do without it.

That was months ago. Recently, I began noticing that I can't concentrate at all, and am so easily distractible that it's interfering with work. Doc prescribed Adderall 20mg twice a day again. But it didn't at all work!!! So doc increased the dose to 30mg in the Am, 20mg in the PM. That did nothing. He then told me just to try 40mg in the AM. NO EFFECT WHATSOEVER. Not even physical side-effects! Doc said that I could try taking 50mg in the AM tomorrow, but I doubt it's going to do anything at this rate... My doc is as puzzled about this as I am. Why doesn't it work at all now, when before it worked so well? It couldn't be that I built up some tolerance to the doses because I only took it for a month and a half a long long time ago.

Has this kind of thing happened to you? Do you know why it happens?

It's not likely to be tolerance. If you're not even feeling physical side effects, it's possible that there is something wrong with the actual pills. Since Adderall is amphetamine, you could buy a home drug test from a pharmacy and test yourself. If the Adderall is real, you should test positive for amphetamines...if not, then it could be that the pills you were given were bad for some reason. Alternatively, it's possible that you might have been given 10mg pills instead of 20mg pills. 10s are usually blue, 20s red.

Still, you should at least feel some effects from them. I take 10mg twice a day, but if I take a half dose, I still feel the effects.

Pdoc kept upping the dose and it really didn't work, so then Pdoc suggest that I may be on too high a dose. He told me to go back down to what used to work before, i.e., 20mg twice a day. And guess what happened???? It worked!!!!

I'm so happy now.

Thanks!