Alpha 2 Adrenergic Agonists

Treatment of hypertensive states (clonidine, guanfacine, guanabenz, alpha methyldopa).

Sedation of mechanically ventilated pts (dexmedetomidine).

Adjunct agent in general anesthesia (dexmedetomidine, clonidine, tizanidine).

Sedation for awake intubation and other minor procedures (dexmedetomidine).

Management of alcohol, nicotine, benzodiazepine, and cocaine withdrawal symptoms via reduction in cardiosympathetic stimulation. Also used for symptom management during naloxone therapy (dexmedetomidine, clonidine).

Additive in central neuraxial and peripheral nerve blockade with efficacy possibly from systemic spread (dexmedetomidine, clonidine).

Reduction in intraocular pressure via decreased aqueous humor secretion (brimonidine, apraclonidine).

Reduction in postop shivering (clonidine, dexmedetomidine)

Treatment of myofascial pain, spasticity, and rigidity (tizanidine)

Treatment of ADHD and impulsivity in children and young adults (clonidine, guanfacine).

Acute Htn after initiation of use mediated by postsynaptic alpha _2B -mediated vasoconstriction

Hypotension and bradycardia mediated by central postsynaptic alpha _2A decreases in peripheral sympathetic outflow and peripheral presynaptic alpha _2A/2C inhibition of NE/EPI release

CV collapse in hypovolemic states or other pts dependent on sympathetic tone or SVR for maintenance of BP (e.g., trauma pts, aortic stenosis).