Green’s Dictionary of Slang

(drugs) Nembutal, a barbiturate.

1949		N. Algren Man with the Golden Arm 214: Lay off the nembie is my advice.
1953		‘William Lee’ Junkie (1966) 23: This night Herman was knocked out on ‘nembies’.
1969		R.R. Lingeman Drugs from A to Z (1970) 190: nemmies [...] nembutal capsules.
1971		E.E. Landy Underground Dict. (1972) 139: nemmie [...] Nembutal.
1983		S. King Christine 387: She’d probably end up taking [...] Nembies or ’Ludes to come down at night.
1993		I. Welsh Trainspotting 91: That’s you goat the set now. Dope, acid, speed, E, mushies, nembies, vallies, smack, the fuckin lot.
2001		ONDCP Street Terms 15: Nemmies — Depressants.