Ketamine Powder/Crystal, sold under the brand name Ketalar among others, is a medication mainly used for starting and maintaining anesthesia.
It induces a trance-like state while providing pain relief, sedation, and memory loss. Other uses include for chronic pain and for sedation in intensive care. Heart function, breathing, and airway reflexes generally remain functional during its effects. Effects typically begin within five minutes when given by injection with the main effects lasting up to 25 minutes.
Common side effects include psychological reactions as the medication wears off. These reactions may include agitation, confusion, or hallucinations. Elevated blood pressure and muscle tremors are relatively common, while low blood pressure and a decrease in breathing are less so. Spasms of the larynx may rarely occur. Ketamine is an NMDA receptor antagonist but it may also have other activity.
Ketamine was discovered in 1962, first tested in humans in 1964, and was approved for use in the United States in 1970. Shortly after its US approval it was extensively used for surgical anesthesia in the Vietnam War, due to its safety. It is on the World Health Organization’s List of Essential Medicines, the most effective and safe medicines needed in a health system. It is available as a generic medication. The wholesale cost in the developing world is between US$0.84 and US$3.22 per vial. Ketamine is also used as a recreational drug.
Ketamine is frequently used in severely injured people and appears to be safe in this group. A 2011 clinical practice guideline supports the use of ketamine as a dissociative sedative in emergency medicine. It is the drug of choice for people in traumatic shock who are at risk of hypotension. Low blood pressure is harmful in people with severe head injury and ketamine is least likely to cause low blood pressure, often even able to prevent it