Introduction
Ketamine is a dissociative anesthetic medicine that has attracted attention due to its psychological advantages as a therapy tool. This rapid review is meant to offer insight into ketamine’s pharmacodynamics, such as its impact on neurotransmitters, receptors, modes of administration, biologic half-life, doses, side effects, drug interactions, contraindications, and therapeutic efficacy.
Neurotransmitters Affected
Ketamine modulates the glutamate system, particularly the N-methyl-D-aspartate (NMDA) receptor, critical in learning, memory, and neural plasticity. By shutting off the NMDA receptor, ketamine leads to dissociative mechanisms, which include a feeling of not being part of yourself and your surroundings. Ketamine affects the glutamate and other neurotransmitter systems, such as dopamine, serotonin, and opioid receptors. The result of these interactions is, however, ketamine’s diverse impact profile, which encompasses its anesthetic, analgesic, and psychedelic properties. The modulation of these neurotransmitter systems has been the reason behind the subjective experiences associated with the administration of ketamine, including the levels of dissociation, analgesia, and altered perception.
Receptors
Ketamine is a non-competitive antagonist at the NMDA receptor, a subtype receptor of the glutamate receptor. (Sial et al., 2020) Similarly, it interacts with other receptors; it is an agonist of the opioid, dopamine, and serotonin receptors, which explains the broad spectrum of the drug’s action.
Rota of Administration and Time of Half-Life
Whether ketamine is administered intravenously, intramuscularly, orally, or into the nose does not influence the effectiveness of treatment. The intravenous administration route is typically employed for the treatment of anesthesia as well as drugs, and this is because the route allows fast onset and precise scrutiny of dosage. These vary in their compatibilities with the standard settings where they are used, and some preferred pathways, such as nasal or oral administration, are implemented instead. Consequently, the relevance of the route of administration is not crucial; instead, the short half-life of ketamine is approximately 2-3 hours. Ketamine works like this: when it reaches the brain, it affects all the synapses that have just been activated. After a few hours, the drug is cleared from the organism. This quick removal limits the period during which ketamine’s effects come on and dissipate, therefore making it appropriate for controlled medical use, but this also adds the possibility of repeated dosages in the abuses of drugs.
Doses
Ketamine is used primarily as an anesthetic in 1-4.5 mg/kg intravenous fluid (Abdollahpour et al., 2020). For treatment-resistant depression as well as for therapeutic purposes in clinical setup, a lower dose (e.g., 0.5 mg/kg) is used to induce a dissociated state, which avoids complete anesthesia.
Side Effects
Ketamine may cause different side effects, such as dissociative symptoms, higher blood pressure and heart rate, nausea, vomiting, confusion, and poor motor coordination (Acevedo-Diaz et al., 2020). Such adverse effects may include psychotic symptoms, like hallucinations and delusions, especially at high doses or a long duration of intake.
Drug Interactions
Caution should be exercised when combining ketamine with other central nervous system (CNS) depressants, such as benzodiazepines, opioids, and alcohol, as it will only potentiate the sedative effects, leading to the risk of respiratory depression (Abdollahpour et al., 2020). However, this may also lead to a negative interaction involving some medications that belong to the CYP and the enzyme system, which may affect the m metabolism and remove those drugs from the body.
Contraindications
Ketamine has a disclaimer that it is strictly prohibited for use in people with severe hypertension, cardiovascular diseases, thyroid disorders, and psychiatric conditions like schizophrenia or acute psychosis (Abdollahpour et al., 2020). It is important to note that the use of ketamine should be avoided in those with a prior history of substance abuse or dependence, as ketamine has the potential for abuse and addiction.
Therapeutic Use and Abuse
Although ketamine is principally prescribed as an anesthetic, it has also proven to be an efficacious and fast-acting antidepressant for major depression and many other psychiatric illnesses. However, over time, it has demonstrated an obscure ability to phenocopy and activate some specific receptors in the brain that lead to dissociation and hallucinations, which might result in its recreational or misuse (Fiorentini et al., 2021). The euphoric state that ketamine, which detaches from one’s inner self and surroundings, places a person in is somehow a mystery because it is pleasurable or enjoyed by the party visitant even though it can transform into an equally unpleasant mode at the exact moment, such as madness and delirium. This risk, in turn, caused a strenuous dialogue about a specific type of control over the medical institutions with special regimes to prevent the recreational usage of this drug as well as the possibility of its inhalation by accident.
Conclusion
Ketamine’s behavior results from it being a ligand that prevents glutamate from acting on the NMDA receptor surface, and it also actively involves different neurotransmitter systems. Indeed, it can be used as a therapeutic aid in depression and is an effective antidote, but the downsides of it can be pronounced, such as overuse or abuse, since it has adverse side effects. The different methods of originating it, the doses needed, associated effects, drug interactions and contraindications of ketamine necessitate interpreting its pharmacology in a well-informed manner. Usage of ketamine should be done with a disclaimer of understanding the variables intimately to allow the administration of this drug in a therapeutic setting without instigating any undesirable results and to optimize its effectiveness for its intended purposes. At the same time, the rest of the job is to be done by enacting/creating prevention coverage, curbing recreational abuse and protecting public safety in general. Nevertheless, a fitting plan can be a lifesaver in such a situation, provided it is capable of ultimately unleashing the therapeutic potential of ketamine, as the only thing that impinges on its pharmaceutical value is the vulnerable risk.
References
Abdollahpour, A., Saffarieh, E., & Zoroufchi, B. H. (2020). A review of the recent application of ketamine in the management of anesthesia, pain, and health care. Journal of family medicine and primary care, 9(3), 1317-1324.
Acevedo-Diaz, E. E., Cavanaugh, G. W., Greenstein, D., Kraus, C., Kadriu, B., Zarate, C. A., & Park, L. T. (2020). Comprehensive assessment of side effects associated with a single dose of ketamine in treatment-resistant depression. Journal of Affective Disorders, pp. 263, 568–575.
Fiorentini, A., Cantù, F., Crisanti, C., Cereda, G., Oldani, L., & Brambilla, P. (2021). Substance-induced psychoses: an updated literature review. Frontiers in psychiatry, 12, 694863.
Sial, O. K., Parise, E. M., Parise, L. F., Gnecco, T., & Bolaños-Guzmán, C. A. (2020). Ketamine: The final frontier or another depressing end? Behavioral brain research, 383, 112508.
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