Green’s Dictionary of Slang

(US drugs) Nembutal.

1969		R.R. Lingeman Drugs from A to Z (1970) 191: nimby nembutal, a barbiturate.
1971		E.E. Landy Underground Dict. (1972) 139: nimby [...] Nembutal.
1981		D.E. Miller Bk of Jargon 327: Nembutal. (nemmies, nimbie, yellowjackets, yellows).
2001		ONDCP Street Terms 15: Nimbies — Depressants.