Dexmeditomidine

Question 1

action

Answer 1

• imidizole compund
• selective a2 agonist
• 8x more specific for a2 than clonidine

Question 2

biotransformation

Answer 2

100% in liver (glucuronidationa and 450)

-reduce dose in liver failure`

Question 3

effect

Answer 3

• sedative and analgesic–easily arousable
• intense analgesia
• sympatholytic and analgesic effects postop, without resp depression
• no amnesia

Question 4

dosing

Answer 4

1ug/kg load, 0.2-0.7 ug/kg/hr infusion for no more than 24 hrs

Question 5

potentiation

Answer 5

-all intraop anesthetic (25% reduction in maintenance requirement of ISO)

Question 6

mechanism of action

Answer 6

• dec formation of cAMP
• inhibit release of NE and termination of propagation of pain signals
• inhibition of firing in spinal cord–>hypotn, bradycardia, sedation, analgesia
• dec bowel motility
• inhibit renin release, inc GFR, inc NA and water secretion
• dec IOP
• decinsulin release
• dec calcium entry into cells, inhibiting neurotransmitter release

Question 7

locus coeruleus action

Answer 7

• noradrenergic nucleus in brain, modulator of vigilance
• nociceptive transmission
• dex has supraspinal site of action–major sedative and antinociceptive effect from this

Question 8

CV

Answer 8

• no direct effects on heart
• Loading dose–transient 5-10 min inc in BP, dec HR< followed by 10-20% dec in BP and stabilization of HR below baseline values
• anti-ischemic effects periop–blunt hemodynamic variability–significantly fewer ischemic episodes

Question 9

respiratory

Answer 9

• less respiratory depression
• some depression and rightward shift of CO2 response curve, maintains resp homeostasis better than other sedative-analgesics

Question 10

neuro

Answer 10

• decreases cerebral blood flow without causing ischemia

- decreases metabolic O2 consumption unaffected

Question 11

contraindication

Answer 11

-pre-existing severe bardycardia, ventricualr dysfunction (EF<30%)-CHF