Ketamine (brand name Ketalar) is a cyclohexanone derivative used for induction of anesthesia. Ketalar is indicated as the sole anesthetic agent for diagnostic and surgical procedures that do not require skeletal muscle relaxation; also, it is indicated for the induction of anesthesia prior to the administration of other general anesthetic agents. Ketamine blocks NMDA receptors through an interaction with sites thought to be located within the ion channel pore region. However, the complete pharmacology of ketamine is more complex, and it is known to directly interact with a variety of other sites to varying degrees. Recently, it was shown that inclusion of the NR3B subunit does not alter the ketamine sensitivity of recombinant NR1/NR2 receptors expressed in oocytes. Likewise, 100 μM ketamine produced only weak inhibition of the glycine-induced current of NR1/NR3A/NR3B receptors. The side effects of ketamine noted in clinical studies include psychedelic symptoms (hallucinations, memory defects, panic attacks), nausea/vomiting, somnolence, cardiovascular stimulation and, in a minority of patients, hepatoxicity. The recreational use of ketamine is increasing and comes with a variety of additional risks ranging from bladder and renal complications to persistent psychotypical behaviour and memory defects. Ketamine was first synthesized in 1962 by Calvin Stevens at Parke-Davis Co (now Pfizer) as an alternative anesthetic to phencyclidine. It was first used in humans in 1965 by Corssen and Domino and was introduced into clinical practice by 1970.

Esketamine is an S(+)-enantiomer of ketamine. It is a nonselective, noncompetitive antagonist of N-methyl-D-aspartate (NMDA) receptor. A nasal spray, containing esketamine, was approved in 2019 for the treatment of treatment-resistant depression in adults, in conjunction with an oral antidepressant, and is marketed under tradename SPARAVATO. Esketamine is a schedule III drug product in the USA.

Dizocilpine (MK-801) is an antagonist of the N-methyl-D-aspartate (NMDA) receptor in the glutamate category involved with the central nervous system (CNS). The drug displays a variety of physiological actions, many of which involve the CNS, such as anesthetic and anticonvulsant properties. It penetrates readily into CNS and was described as the agent with central sympathomimetic properties. Co-administration of dizocilpine with psychostimulants, such as cocaine, amphetamine and nicotine, has been reported to prevent the development of behavioural sensitization to these drugs as well as associated neuroadaptations in rodents. However, studies with bromocriptine have suggested that co-administration of dizocilpine might merely cause sensitization to become state-dependent. A single injection of MK-801 to rats models both positive and negative symptoms of schizophrenia. Treatment of mice with dizocilpine induced learning impairment.

Methoxetamine (abbreviated as MXE) is a novel psychoactive substance that is emerging on the Internet and induces dissociative effects and acute toxicity. MXE acts behaviourally as a typical dissociative anesthetic with stimulant and anxiogenic effects at lower doses, sedative/anesthetic effects at higher doses, and as a disruptor of sensorimotor gating. Its pharmacological effects have not yet been adequately investigated, but recently published articles shown, that MXE differentially affected motor activity, behavior and emotional states in rats, depending on the dose tested. Methoxetamine acts mainly as N-methyl-D-aspartate (NMDA) receptor antagonist and a serotonin reuptake inhibitor.