Ketamine is a dissociative anesthetic medication that was first synthesized in 1962 by a chemist searching for a novel compound with the anesthetic efficacy of older dissociative anesthetics such as PCP but with a much greater safety profile and lower incidence of “emergence reactions.” Emergence reactions are untoward, uncomfortable reactions that may be experienced while the medication is wearing off, causing hallucinations, anxiety, and other unpleasant psychic symptoms.
A dissociative anesthetic is named such as at higher doses it can cause a sense of the patient being dissociated or “out of body” for a time. At the lower doses used for mental health disorders, this effect is not typical, but milder side effects such as altered perceptions or a sensation of floating frequently occur.
Due to ketamine’s favorable safety profile, it rapidly replaced morphine as the “buddy drug” given by soldiers to their wounded comrades in pain on the battlefield during the Vietnam War, and is still being used on battlefields today. Ketamine was found to be a much safer and effective analgesic than the previously used opiate medications, as it did not lower the blood pressure or slow the patient’s breathing and did not require the use of cardiac monitoring.
Ketamine has been and is currently used extensively in emergency departments for analgesia and sedation in children, and more recently in adults, who are about to undergo painful or delicate procedures, in which creating a dissociative, amnestic state is favorable. This includes fracture reductions and repair of disfiguring or extensive lacerations in frightened children. As a result, ketamine is the anesthetic of choice for pediatric analgesia and sedation in the ED.
Most recently, the administration of intravenous low-dose ketamine has been found to be surprisingly effective in rapidly improving the symptoms of depression, posttraumatic stress disorder (PTSD), obsessive-compulsive disorder (OCD), and other mental health conditions, as well as chronic pain syndromes. This effect is supported by myriad studies conducted at reputable research centers from 2000 to the present.
Ketamine has been shown to improve symptoms of depression in as little as several hours after the first treatment. This lifting of the depressive symptoms seems to lasts anywhere from several days to weeks or months, and typically lasts longest after a series of six infusions over a two-week period. Single-dose “booster” treatments at a period of two weeks to months after the initial infusion have been shown to prolong the antidepressant effect of the medication in many patients.
In 2014, Thomas Insel, former Director of the National Institute of Mental Health, stated that, “Recent data suggest that ketamine, given intravenously, might be the most important breakthrough in antidepressant treatment in decades.”