Ketamine is a general anesthetic widely used in operating rooms since the 1970s. In the late 1990s, researchers at Yale first showed that a subanesthetic (low-dose) intravenous infusion of ketamine had rapid and profound antidepressant effects. Subsequently, a large (and growing) research literature evolved over the next 20 years demonstrating the efficacy of ketamine infusion therapy to help patients with TRD, bipolar depression, suicidal ideation, PTSD and other anxiety disorders.
Ketamine acts differently than commonly used antidepressants like Prozac and Lexapro (known as “SSRIs”). Unlike these medications that act on serotonin, ketamine is thought to act on NMDA (N-methyl-D-aspartate) receptors and to stimulate glutamate activity. Glutamate is a neurotransmitter that is critical in helping the brain change by making new neural connections.
Because the ketamine infusion is given intravenously and is considered a controlled substance, it must be administered by specially trained medical personnel in a certified clinical setting. Most patients receive it as an outpatient and go home in a couple of hours.