skittles noun dextromethorphan (DXM), an active ingredient in non-prescription cold and cough medication, often abused for nonmedicinal purposes US
Youths’ nicknames for DXM: Robo, Skittles, Triple C’s, Rojo, Dex, Tussin, Vitamin D. DXM abuse is called “Robotripping” or “Tussing.” Users might be called “syrup heads” or “robotards.” — USAToday, p. 1A, 29 December 2003