There are probably side effects, like you becoming like the target, but those are manageable of you take a bit each day and let your self assert control.
If you want them to die fast, you have a blow orgy, where lots of people come over to help you snort it.
Used to cut cocaine.
Use for your urban fantasy game, or as a sideline in your dark superhero game.
Plot idea: The blow party got raided, and the last bit of cannibal cocaine that is needed to destroy the target (who is somehow affiliated with your heroes) is sitting in the evidence locker. The bad guy wants to get it out and use it up. The heroes want to retrieve it and somehow reverse the process. Merriment ensues.