Dexmedetomidine

Question 1

mechanism of action

Answer 1

1. -non-selective alpha2 agonist
   - inhibits adenylate cyclase
   - modulates ion channels
   - alpha2B & alpha2C receptors in CNS lead to sympatholysis, sedation, anti-nociception
2. sedation- receptors in locus cereleus (LC)
3. analgesia- receptors in LC and SC

Question 2

decreased activity of LC to VLPO d/t…

Answer 2

• increase GABA/galanin release in TMN -> decrease histamine release in cortical/subcortical areas
• inhibits ion conduction thru VGCa++ activated K+ channels

Question 3

CV effects

Answer 3

decrease HR, SVR, CO, SBP, contractility

Question 4

pulmonary effects

Answer 4

decrease minute ventilation but able to maintain CO2 response

Question 5

CNS effects

Answer 5

unknown, possible neuroprotection

Question 6

premedication dose

Answer 6

0. 33-0.67 mcg/kg 15 min before surg
   - decrease induction dose & MAC
   - decrease post-op opioid requirements

Question 7

MAC dose

Answer 7

1 mcg/kg over 10 min

0.7 mcg/kg/min keeps BIS 70-80

Question 8

Uses

Answer 8

• peds with IV
• “wake up” period
• “IV N2O” to avoid S.E.
• MAC cases
• reduce PONV