I avoid all (non-alcohol) drugs at all times on planes as I have seen how they can react very badly with alcohol, causing some very unpredictable behaviour in other passengers.

Sometimes a glass of wine or a short helps, but what always works for me is eyeshades, ear plugs and then my own noise-cancelling headphones over the earplugs playing classical music or a classic rock album. I don't lay the bed flat - I leave the pillow end a little raised and close my eyes while lying face up. This combo always works for me.