. Author manuscript; available in PMC: 2012 Nov 1.

Published in final edited form as: Anesth Analg. 2011 Sep 14;113(5):1188–1191. doi: 10.1213/ANE.0b013e31822b8a7d

Table 1.

Direct and indirect acting N-Methyl-d-Aspartate (NMDA) receptor antagonists. Drugs known to antagonize the NMDA receptor by binding to the NR1 or NR2 subunit are considered to be direct acting. Whereas, drugs that antagonize the NMDA receptor through an alternative method are considered indirect acting.

Drug	NMDA receptor antagonist Citations
	Direct Acting	Indirect Acting
Dextromethorphan	21
Ketamine	17, 18, 21
Methadone	22
N₂O	14, 16, 19
PCP	17
Pentobarbital		18, 19
Propofol		19

PCP = phencyclidine

N₂O = nitrous oxide