did you try sleeping for a couple of in-game days?
I drank a couple of vodkas, and I went on to complete like three side quests taking a good 2 hrs in real life, and all the sudden after the last quest it said the vodka effect had worn off....so it might just take a while if you used a lot of them
hope this helps!
thanks, played for 3hrs (not ingame) then the effect was removed.
good tip.