NMDAR antagonist
NMDA receptor antagonists are a class of anesthetics that work to antagonize, or inhibit the action of, the N-Methyl-D-aspartate receptor (NMDAR). They are used as anesthetics for animals including humans; the state of anesthesia they induce is referred to as dissociative anesthesia.
Several synthetic opioids function additionally as NMDAR-antagonists, such as pethidine, methadone, dextropropoxyphene, tramadol and ketobemidone.
Some NMDA receptor antagonists, such as ketamine, dextromethorphan (DXM), phencyclidine (PCP), methoxetamine (MXE), and nitrous oxide (N2O), are popular recreational drugs used for their dissociative, hallucinogenic, and euphoriant properties. When used recreationally, they are classified as dissociative drugs.
NMDA receptor antagonists induce a state called dissociative anesthesia, marked by catalepsy, amnesia, and analgesia. Ketamine is a favored anesthetic for emergency patients with unknown medical history and in the treatment of burn victims because it depresses breathing and circulation less than other anesthetics.Dextrorphan, a metabolite of dextromethorphan (one of the most commonly used cough suppressants in the world), is known to be an NMDA receptor antagonist.
...
Wikipedia