Green’s Dictionary of Slang

barbiturates.

1969		R.R. Lingeman Drugs from A to Z (1970).
1971		E.E. Landy Underground Dict. (1972).
1981		A. Payne ‘You Need Hands’ Minder [TV script] 53: So how about letting me have the barbs back?
1994		I. Welsh ‘Eurotrash’ in Acid House 30: She bought some barbs, took them.
1996		R. Rendell Keys to the Street 273: The pharmacy where his mother’s repeat prescription for barbs was regularly dispensed.
2002		L. Pizzichini Dead Men’s Wages (2003) 125: Barbs close your mind rather than expanding it.