A Benadryl and a few drinks early in flight / pre-departure. Lots of water before landing. Nothing stronger. Why?
(1) Once took an Ambien and didn't fall asleep. I felt miserable yet knew I couldn't get up.
(2) Once took something else and didn't fall asleep. I was so dizzy I almost fell over when trying to visit the loo.
(3) Once took off on a red-eye and landed an hour later due to mechanical. I decided never to take anything that would make me not functional if I need to leave the plane before the pill wore off.