[atari 2600]

I wouldn't sweat it too bad. Even if it's only been a couple of days since you took the pill(s), if you come up testing postive for opiates, then you could always just say you had used a cough syrup recently with codeine in it, like Brontex, and they'll just have you do a re-test in a few days. The problem there is that they may ask to see your prescription for the cough medicine possibly. You could say you used someone else's presription cough medicine though and I doubt they'll crack the whip too hard over something like that.

What you want to do is drink plenty of water beforehand. Never give the test the first piss of the day and try as best you can to deny the test the first bit of your urine stream. In other words, pretend you can't go, take away the container, and then start taking a piss and slide the container in under your stream after you've already started to piss. The first part of the stream is where the majority of the detectable substances are. To be extra precautious, you may want to dab the stream for a split-second with a fingertip that has a little bleach on it from earlier in the day, but I hear now they can detect for bleach traces and thus the results are thrown out as inconclusive. Somehow, I doubt this is the case, but since I haven't been tested in a long, long time, I just do not know for sure.