Shouldn't a 10 mg dose of XR last twice as long as two 5 mg doses of IR?

I don't think so. I think the amount that's digested at the various intervals is just higher, meaning it's effect is larger, not longer.

Certainly not as long as they like to claim it will, IMO. I dislike that very intensely and expect to return to Concerta ASA I see my psydoc on the 18th.

If I take my 20mg dose by 7:00 am, by noon to 1 pm range I'm toast, barely able to keep my eyes open at times right after it drops me like a rock...

Nope. Adderall XR is just two regular pills combined into one for ease of use.
Taking a 10mg XR = 5mg IR twice a day.
For someone taking 20mg of XR twice a day = 10mg IR four times a day.
For someone taking 40mg of XR once a day [(2) 20mgXR at the same time] = 20mg IR twice a day.

and so on... :)

J

If I take my 20mg dose by 7:00 am, by noon to 1 pm range I'm toast, barely able to keep my eyes open at times right after it drops me like a rock...Glad to know its not just me who has this going on! I become unbearably tired after eating when I have taken my Adderall in the AM.

XR only lasts me about six hours and then drops off....it would work better for ME if I could have taken a second XR in the middle of the day....for me, it just doesnt last very long....

Adderall XR works well for me only if I take one 25mg dose about half an hour before I get out of bed in the AM and then another 25mg dose at noon. I've used regular Adderall, but like many people, have found the different generics give different results: from very good, to very poor. Keith :cool: