An Overview of Ketamine

Ketamine's anesthetic effects are principally produced through its numerous interactions with the central nervous system. First, ketamine inhibits glutamate excitatory transmission by antagonizing NMDA receptors, resulting in sensation and perceptual separation. Ketamine also amplifies the effects of gamma-aminobutyric acid (GABA), which further inhibits central nervous system activity. Ketamine also acts on the endogenous opioid system, with studies indicating that it can reduce pain by boosting the release of endogenous opioid peptides. Ketamine inhibits autonomic nervous system reactions and lowers respiratory secretions by decreasing acetylcholine release, making anesthesia safer and more comfortable. Ketamine's impact on the central dopamine system may also contribute to its analgesic and psychoactive effects. Through these multiple pathways, ketamine achieves efficient anesthesia. Additionally, S(+)-ketamine is considered more effective than the R(-)-isomer in terms of anesthesia and analgesia, with its anesthetic potency being three to four times that of the R(-)-isomer.

Figure 2. Sites of action of ketamine and other drugs in the pain signaling pathway.
(Source: Gorlin AW, et al. 2016)

The perioperative application of ketamine requires attention to possible side effects, including postoperative nausea, vomiting, elevated heart rate, and blood pressure fluctuations. When using ketamine, clinicians should be cautious of potential increased intracranial pressure, especially in patients with space-occupying brain lesions or brain injuries. Slow injection of ketamine can reduce central respiratory impacts and minimize the risk of transient respiratory arrest associated with rapid injection.

Abuse of Ketamine

While ketamine has broad therapeutic potential, its side effects must not be overlooked. The side effects of ketamine can be categorized into physiological and psychological aspects, especially with long-term use or abuse, which may lead to severe adverse reactions.

Ketamine's psychological side effects are highly noticeable. After the initial usage, patients frequently have "dissociative experiences," in which they feel separated from themselves or their surroundings, with altered perceptions of time and space, resulting in panic or anxiety. Ketamine at high dosages can also cause hallucinations and delusions, with patients seeing or hearing things that do not exist or holding absurd ideas. These symptoms are more common in ketamine misuse and can progress to schizophrenia-like psychotic behavior. Ketamine can create emotional instability in patients, ranging from tremendous exhilaration to deep sadness. Long-term use of ketamine may result in cognitive impairment, including memory loss, reduced attention, and executive function disorders. These cognitive issues can significantly impact a patient's work and learning, with some damage potentially being irreversible.

Aside from psychological side effects, ketamine's physiological adverse effects are significant, particularly during the perioperative phase and after long-term use. Although ketamine has good bronchial dilation capabilities in anesthetic induction, excessive dosages might cause respiratory depression or apnea. This danger increases with rapid infusion, necessitating close monitoring of the patient's respiratory condition. Rapid ketamine injection can also induce a rise in heart rate and blood pressure changes, which are especially noticeable in individuals with hypertension or heart disease and should be used with caution. Ketamine use can cause nausea, vomiting, and gastrointestinal discomfort, which are common in the early postoperative period and can typically be addressed with symptomatic medicine. However, long-term ketamine use or abuse can affect the urinary system, causing cystitis and renal failure. Patients may experience difficulties urinating, hematuria, and bladder pain; in severe cases, surgical intervention may be required.

Finally, because of its unusual chemical structure and various modes of action, ketamine has vast application prospects in anesthesia and the treatment of mental illnesses. Despite its high efficacy in treating major depressive disorder, treatment-resistant depression, and suicidal ideation, it is associated with possible adverse effects and misuse hazards. To guarantee safe and effective ketamine treatment, practitioners must properly assess the risks and benefits, design suitable treatment plans, and closely monitor patients' physiological and psychological states. Healthcare workers can improve their use of ketamine by studying its molecular biological properties, pharmacological mechanisms, therapeutic applications, and adverse effects. High-quality antigens, antibodies, and ELISA kits can support in-depth exploration of ketamine's potential applications and safety. We also offer a variety of products related to metabolites such as Norketamine, Dehydronorketamine, and Fluoroketamine. With comprehensive quality control products, Creative Diagnostic ensures your experiments are safeguarded. Please visit our product page for ordering.