slip someone a Mickey

slip (one) a Mickey (Finn)

To put a drug in someone's drink that will make them lose consciousness and incapacitate them; to serve someone a drink laced with such a drug. Please be careful—it's scarily easy for someone to slip you a Mickey at big parties like that. The victim of the robbery stated that the assailant had slipped him a Mickey Finn at the bar.
See also: mickey, slip
Farlex Dictionary of Idioms.

slip someone a Mickey

tv. to secretly put a Mickey Finn in someone’s alcoholic drink. (This drug either makes the victim pass out or causes immediate diarrhea.) Somebody slipped Marlowe a Mickey and sent him into action.
See also: mickey, slip, someone
McGraw-Hill's Dictionary of American Slang and Colloquial Expressions
See also:
  • slip (one) a Mickey (Finn)
  • slip a Mickey
  • slip someone a Mickey Finn
  • drink (oneself) to sleep
  • drink (someone) under the table
  • drink somebody under the table
  • drink someone under the table
  • drink under the table
  • What are you drinking?
  • What are you having?