Dexmedetomidine

Chemical

Imidazole derivative & active d-isomer of medetomidine with analgesic, anxiolytic & sedative activities

Use

  1. Sedation
  2. Anxiolysis
  3. Analgesia
  4. Antihypertensive

Presentation

Clear, colourless solution

D-isomer of medetomidine → ∴Dexmedetomidine

→ only the D-isomer is active

100mcg/mL in 2mL vial

Dose

1mcg/kg over 10 mins (load)

Then 0.2 – 0.7mcg/kg/hr infusion titrated to effect

Route

IV

Onset

15 mins

MoA

  • Activates pre-synaptic α2 adrenoreceptors in CNS → ↓NA release

∴ ↓symp outflow

  • α2 agonism in CNS → sedation & anxiolysis
  • α2 agonism in AS/C fibres → analgesia
  • α2 agonism in CNS/SC → ↓symp outflow → ↓HR, VD
Dexmedetomidine

PD

CNS

  • Sedation
  • Anxiolysis
  • But does not cause Resp D
  • Gives sedation in a cooperative & semi-rousable state

Resp – none

CVS – ↓MAP, ↓HR

PK

A

IV only

Unpredictable PO

D

High PPB 94%

Low VD 1.3L/kg

M

Hepatic, extensive glucuronidation & N-methylation

E

Metabolites in urine

t ½ B – 2hrs

Clearance 39L/hr

Adverse Effects

  • Hypotension
  • Bradycardia
  • Nausea
  • Dry mouth