Ketamine keeps patients breathing under anaesthesia, which made it a battlefield drug
Most anaesthetics slow breathing and drop blood pressure. Ketamine does the opposite: patients keep their airway reflexes and their hearts are stimulated. That odd profile made it a field surgery staple in the Vietnam War. Decades later, in 2000, researchers found it could lift depression within hours, reshaping a drug first made in 1962.
Chemists synthesised ketamine in 1962 as an offshoot of phencyclidine, hoping for a safer anaesthetic with fewer hallucinations, and the United States approved it in 1970. It blocks NMDA receptors in the brain and exists as two mirror-image forms, esketamine and arketamine. At full doses it produces dissociative anaesthesia, a trance combining pain relief, sedation and memory loss. It is on the World Health Organization's essential medicines list and is sold as a generic.
Its safety margin explains where it shines. Because it barely suppresses breathing and tends to raise blood pressure, it suits trauma patients in shock, people with severe head injuries, and emergency care outside hospital. It widens the airways, so it can be used in asthma or active bronchospasm, and children with certain heart and neuromuscular conditions are good candidates. A 2011 guideline endorsed it for sedation during painful emergency procedures. At lower doses it eases acute pain about as well as opioids in emergency departments, reduces morphine needs after surgery and can give short-term relief in some neuropathic pain.
The depression story moved fast after 2000. In 2019 esketamine was approved in Europe, and American regulators cleared it as a nasal spray for depression that resists other treatment; a Canadian guideline ranks it third-line. Some evidence suggests the original mixed form may work better and longer at higher doses. In 2026 France approved intravenous ketamine for severe suicidal crisis, the first official rapid-acting option for imminent risk, though reviews describe the supporting evidence as largely low quality and long-term effects as uncertain.
The same trance draws recreational users, who call it K or Special K, so the drug is tightly controlled. Heavy regular use has been linked to liver and urinary damage, and case reports now describe bladder problems in young people. Psychological side effects limit its appeal in operating theatres, and it is avoided in severe heart or liver disease and uncontrolled psychosis. The long-term consequences of repeated use are still being studied.
Source: Ketamine
