WordNet (r) 3.0 (2006):

Mickey Finn
    n 1: slang term for knockout drops

Moby Thesaurus II by Grady Ward, 1.0:

104 Moby Thesaurus words for "Mickey Finn":
   Amytal, Amytal pill, Demerol, Dolophine, H, Luminal, Luminal pill,
   M, Mickey, Nembutal, Nembutal pill, Seconal, Seconal pill, Tuinal,
   Tuinal pill, alcohol, amobarbital sodium, analgesic, anesthetic,
   anodyne, aperitif, barb, barbiturate, barbiturate pill,
   black stuff, blue, blue angel, blue devil, blue heaven,
   blue velvet, calmative, chaser, chloral hydrate, cocktail, codeine,
   codeine cough syrup, depressant, depressor, doch-an-dorrach, dolly,
   dope, downer, drink, drug, eye-opener, goofball, hard stuff,
   heroin, highball, hop, horse, hypnotic, junk, knockout drop,
   knockout drops, laudanum, liquor, lotus, meperidine, methadone,
   mixed drink, morphia, morphine, narcotic, nightcap, opiate, opium,
   pacifier, pain killer, pain-killer, paregoric, parting cup,
   pen yan, phenobarbital, phenobarbital sodium, pousse-cafe, punch,
   purple heart, quietener, rainbow, red, scag, secobarbital sodium,
   sedative, shit, sleep-inducer, sleeper, sleeping draught,
   sleeping pill, smack, sodium thiopental, somnifacient, soother,
   soothing syrup, soporific, stirrup cup, sundowner, tar,
   tranquilizer, turps, wee doch-an-dorrach, white stuff, yellow,
   yellow jacket