tough situation, but always keep in mind, if whomever is testing you (especially for a certain substance like amphetamines in general), im sure they'll be able to break down what's found in your piss/blood to sub-categories of what exactly it was you took to show up positive.. they put enough money into testings, which im assuming isnt just for you, but probably many others too, so they'll probably make sure they do it right..
HOWEVER.. if you did, hypothetically of course, show up positive for amphetamines, you could always bide yourself some time by telling them about your prescribed inhaler.. it'd throw em off for a day or two while you hired yourself a nice lawyer in case you decide (and only with the knowledge that your lawyer is one of supreme "lawyerness" and will be able to defend to the death your problem) to file a suit against the fuckers for discriminating against you for a medication you need to take "in order to live" (hype it up of course if this isnt the case)..
the justice system (at least here in canadia) is one of supreme fairness from what ive noticed in the past few months, and unless the test they give you shows up for "JIB THIS BIG BLACK GUY WHOM CALLS HIMSELF 'CASH-MONEY' ON THE CORNER HOOKED ME UP WITH LAST WEEK" (;b @ entropy cru), you'll be fine ;b
good luck and god bless,
cooey.