Dexmedetomidine (DEX) is an α2 adrenoceptor agonist that is commonly administered before general anesthesia as a short-term sedative [1–3]. In this setting, dexmedetomidine has several well-studied benefits, most notably a reduction in the need for opioids during surgical procedures while producing sedation and analgesia throughout the entire perioperative period, as well as an elimination of otherwise common post-surgical respiratory depression [1–2]. Patients under the effect of dexmedetomidine retain psychomotor functions without sacrificing comfort, allowing for cooperation and physiological arousal . First approved for ICU use in December 1999 and used at Baylor University Medical Center in August 2000, dexmedetomidine is commonly sold under the trade name Precedex today [2–3].
As an α2 adrenoceptor agonist, dexmedetomidine targets presynaptic receptors in the peripheral and central nervous systems, as well as in platelets, the pancreas, eyes, kidneys, and liver . Via a negative feedback mechanism, this imidazole compound regulates norepinephrine and adenosine triphosphate levels . α2 receptor agonists activate guanine-nucleotide regulatory binding proteins that activate cellular responses through two primary methods: the modulation of ion channel activity or the firing of a second messenger system . The former of these methods produces the hyperpolarization of the cell membrane, facilitating the expulsion of potassium and, consequently, suppressing neuronal activity .
Dexmedetomidine differs from other means of sedation because of the combined effects of presynaptic and postsynaptic α2 adrenoceptor activation . Presynaptic activation preserves norepinephrine levels, effectively stifling pain signals, while postsynaptic activation centralized in the central nervous system contributes to reduced sympathetic activity . These two forms of activation enable dexmedetomidine to become a singular source of sedation, anxiolysis, and analgesia . Consequently, some of the challenges associated with the administration of several disparate medications are eliminated . However, despite this knowledge, dexmedetomidine’s analgesic mechanisms are not yet fully understood .
In anesthetic contexts, dexmedetomidine can be administered intravenously or intrathecally, although intravenous administration is more common . Numerous studies have revealed that dexmedetomidine can result in as much as a 50% decrease in opioid consumption through the surgical process [4–5]. When managing refractory cancer pain, combined treatments consisting of dexmedetomidine and opioids have even been considered optimal in terms of analgesic effects in comparison to opioid-only treatments . Additional noted effects, including diminished delirium in non-cardiac surgeries in elderly patients , improved recovery after laparoscopic colectomy , and reduced depression rates following cancer treatment , demonstrate the widespread benefits of this agonist.
However, it is important to note the side effects previously observed following dexmedetomidine administration, including hypotension, hypertension, nausea, bradycardia, and dry mouth . These side effects were observed immediately during or following loading; consequently, they can be diminished by controlling the loading dose . Additionally, patients might be afflicted by withdrawal, similar to that associated with clonidine, following treatment .
Scientists continue to investigate the power of dexmedetomidine use, particularly concerning its effects on children. A notable recent study  demonstrated how dexmedetomidine can reduce inflammatory factors and ameliorate cardiopulmonary bypass-resultant neurodevelopmental damage when treating adolescent congenital heart disease. Another study  compared how minimal dosages of dexmedetomidine and midazolam prevented emergency delirium in children following exposure to sevoflurane anesthesia. Although both medications had equal efficacy when administered at the end of surgical procedures, dexmedetomidine had significantly higher postoperative efficacy.
Evidently, the extent of dexmedetomidine’s potential is still being discovered by the scientific community and, thus, the medication remains a powerful tool in the anesthetic sphere.
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