This happened unintentionally but I realize in retrospect it was very lucky.

I was on a red-eye from Abu Dhabi to London scheduled to leave around 2 am and arrive at Heathrow around 7 am. I had some Dramamine with me and had planned to take it after boarding but I decided to hold off.

Luckily for me, after a few hours waiting on the plane at the gate, the flight was cancelled sometime around 5 am. I spent the next 4 hours figuring out my travel plans in a frantic middle eastern airport during the morning rush. I often think how much more hellish it would have been had I been artificially drowsy on top of my lack of sleep.