Last time I heard of pilots taking these, a Canadian ground unit in Afghanistan ended up on the wrong end of a pair of MK82s from F-16s. These drugs impair judgement. I would not take them unless I were alone in the cockpit and unable to stay awake. That is how they are prescribed by military flight docs for single-seat ocean crossings behind a tanker.
PS- They are a wonderful party drug though if you are looking to push through the night after drinking on the back side of the clock. Not that I've ever done such a thing.