Dexmedetomidine (Precedex) is a selective intravenous alpha-2 agonist approved for sedation in non-intubated patients in the perioperative setting and short-term sedation for patients on mechanical ventilation. A negative feedback loop is potentiated by binding alpha-2 receptors, decreasing the further release of neurotransmitters from the pre-synaptic neuron. This reduces the sympathetic outflow, which can lead to bradycardia and hypotension. Despite the 1600 to 1 ratio for alpha-2 : alpha-1 receptor selectivity, sometimes hypertension can be noted (especially with boluses) through alpha-1 and alpha-2B subtype receptor activation.
As an intensivist, I often use dexmedetomidine to transition patients off mechanical ventilation. I’ll continue a low-dose infusion during extubation to smooth out emergence because it doesn’t significantly depress the respiratory drive and provides some degree of analgesia and anxiolysis. I’ll also consider nocturnal infusions to simulate patterns found in non-REM sleep and run an infusion to mitigate the sympathetic effects of alcohol withdrawal.
As a cardiac anesthesiologist, I often use dexmedetomidine as an anesthetic adjunct, as an anxiolytic, and to transport patients who are still intubated to the ICU. In both the OR and ICU, I’ll also consider using this medication for procedural sedation. It’s a cornerstone of many of my TIVA cases.
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