Substance Abuser Achievement
Drink beer while on steroids or vice versa in SP
When you have both beer and steroids in your inventory take them both, one after the other and the achievement will unlock. This is an easy achievement if you saved the beer from the gym and used both after finding the steroids. Both can be found in The Duke Cave.
See "Flagon of Chuckles" and "Juiced" for locations within The Duke Cave.