Ketamine's dual role: From anesthetic to antidepressant

Ketamine was first synthesized by the American chemist Calvin Stevens in 1962 at the University of Michigan. It was initially employed as a new anesthetic agent. It is an organic chemical compound with the molecular formula C₁₃H₁₆ClNO and a 237.73 g/mol molar mass. The pharmacological action of ketamine primarily involves NMDA receptor antagonism, similar to compounds like dextromethorphan and phencyclidine. However, ketamine is distinguished by its significantly shorter action and fewer side effects, making it popular in medicine for many years.

Ketamine induces a specific type of anesthesia known in medicine as "dissociative anesthesia." It selectively inhibits certain structures of the central nervous system, leading to a loss of consciousness while simultaneously stimulating others. It causes symptoms such as catalepsy (specific muscle rigidity), eye movements, or hallucinations. The dose of ketamine that induces anesthesia ranges from approximately 1 to 2 mg/kg of body weight.

On both global and Canadian drug markets, new synthetic drugs, often referred to as modified or designer drugs, continue to appear. These are usually derivatives of "classic" psychoactive substances, including medications. An example is methoxetamine, a structural analogue of ketamine. Ketamine itself is sometimes used as a recreational drug because improper and uncontrolled use can induce sensations of detachment from one's body, occasionally accompanied by euphoria and even hallucinations.

Unfortunately, these symptoms are only temporary. The subsequent consequences of recreational ketamine use include abdominal pain, nausea and vomiting, seizures, memory and concentration disorders, vision problems, and paranoia. All of these negatively affect health, well-being, daily life, and interpersonal relationships. Ultimately, it leads to deterioration and can pose a direct threat to life, similar to many other drugs.

Interestingly, the illegal use and abuse of ketamine began shortly after its introduction to the market, specifically in 1970. Returning soldiers from Vietnam, who had ketamine used on them as an anesthetic, described vivid hallucinations. Initial reports also emerged regarding the misuse of this medication by healthcare workers. In recent years, ketamine has been termed a club drug because it is frequently used during various types of parties. Repeated administration of ketamine leads to the development of behavioural tolerance, meaning that increasingly larger doses are necessary to achieve the desired narcotic effect.

Numerous scientific studies have confirmed that ketamine, when used in moderate, controlled amounts, can have antidepressant effects. This is especially true for patients with severe forms of depression that do not respond to traditional pharmacotherapy methods. One study found that the depression symptoms in patients taking specific doses of ketamine significantly improved within a few hours after administering a single dose. Meanwhile, a single infusion of ketamine typically exerts a rapid antidepressant effect, which can last for several days. During this time, psychotherapy, essential for achieving long-term remission of the disorder, can be initiated.

Previously used antidepressant medications are the first-line treatment for patients diagnosed with depression. Often, they prove effective; however, for 40% of patients, the effects are insufficient, and the longer wait time for full efficacy is a drawback. Therefore, ketamine appears to be a promising medication for the future treatment of depression, requiring further, careful scientific study.

References

1. Messer M., Irina H., Ketamine maintenance therapy allows for long-term remission in depression, Psychiatry after Graduation, 3/2010.

2. Pochwat B., Ketamine – a long journey from anesthetic to prototype antidepressant medication. Review of potential mechanisms of action, Psychiatry Poland 2022; 56(5): 1017–1032.

3. Ross S., Ketamine and Addiction, Psychiatry after Graduation, 2/2009.

This material is presented as part of a collaboration with Patronite.pl. The author is Kamil Radlak - Portal Fizjoterapeuty. You can support the author directly on his Patronite profile https://patronite.pl/fizjoterapeuty