Ketamine was discovered in 1962. It was licensed for use as an anaesthetic agent in 1970. Ketamine in on the World Health Organisation list of essential medicines, as it produces reliable anaesthesia and analgesia without prominent respiratory or cardiovascular adverse effects.
Ketamine is frequently used in emergency situations such as procedural sedation in emergency departments and for transporting patients via road or air ambulance.
More recently, the rapid onset of antidepressant effects due to administration of low doses of ketamine has been discovered and is being used to help patients with severe forms of depression, anxiety, and other forms of mental disorder.
Ketamine can be given via intravenous, subcutaneous or oral routes, with differing effects and side effects. High doses of ketamine typically produce a feeling of dissociation and may produce hallucinations.
Typically, the side effects of a dose of ketamine begin to wear off after about one hour. Ketamine can be abused by injection or insufflation (snorting).
Positive effects on mood or anxiety are noticed by about two thirds of patients following administration of an adequate dose, and the onset of these benefits may begin within hours of treatment.
It is common for depression symptoms to recur within 3-7 days, and this means that patients need to take further doses several times per week. As treatment progresses, doses can be more widely spaced.