A polysyllabic exercise in typographic errors, dexmedetomidine is a drug more commonly known by its trade name “Precedex.” It was FDA approved in 1999 and has obtained an expanded role in emergency rooms as a generic version has tilted costs downward over the past few years. A 4 mcg/mL manually mixed generic concoction costs about $23 with the trademarked version costing $50. You can have the pre-mixed version for about $50 as well (which appears to be under patent past 2030).
FDA approved indications include sedation for ICU patients that are intubated for less than 24 hours and as a premedication for sedation though the non-FDA uses vary immensely.
It works as an alpha-2 agonist that sedates while providing analgesia through both spinal cord and peripheral antinociception. It works at the locus ceruleus in the medulla to halt transmission of noradrenergic output. This differs from GABA based medications which do not halt sympathetic transmission. Side effects include bradycardia and hypotension. Rapid administration activates alpha 2b receptors and causes vasoconstriction with resultant hypertension/reflex bradycardia. It is metabolized by the liver.
Our case today involves the following head CT of a patient brought to the emergency room unresponsive. They would no longer protect their airway and were subsequently intubated.
Sedating with propofol may be a good idea but what about dexmedetomidine?
Dexmedetomidine is a useful tool in managing patients with increased intracerebral pressure with whom you would like to maintain a salvageable neurologic exam. When sympathetic overdrive is a concern, it provides lysis to that environment creating a more stable environment. It creates a mild decrease in ICP and decreases CNS glutamate/catecholamines. If light levels of sedation are used with precedex, patients will rouse easily and then return to sedation when left alone. They simply aren’t as confused because GABA receptors are not the pharmacologic target.
To use dexmedetomidine you start with a 0.2-0.7 mcg/kg/hr infusion. The bolus should probably be avoided to avoid hemodynamic surprises.
Do you have success employing dexmedetomidine in your ER workflow?
Goldfrank, L. R., & Flomenbaum, N. (2006). Goldfrank's toxicologic emergencies. New York: McGraw-Hill.
Lee, K. (2018). The neuroICU book. Ch 20