Well I certainly wouldn't use the real thing:
Medicinal Action and Uses---The powdered berries are sometimes used as an ointment for destroying lice; the entire fruits are used to stupefy fish, being thrown on the water for that purpose. Picrotoxin is a powerful convulsive poison used principally to check night sweats in phthisis by its action in accelerating respiration, but it is not always successful. It was at one time used to adulterate beers, increasing their reputation as intoxicants; it is an antidote in Morphine poisoning.
I'm sure the flavor contribution was extreme bitterness.
If you want a more nuanced and safer, and IMO, good tasting intoxicant enhancer try yarrow. It has a very slight euphoric effect, much better than a narcotic effect.