Dexmedetomidine
Chemical
Imidazole derivative & active d-isomer of medetomidine with analgesic, anxiolytic & sedative activities
Use
- Sedation
- Anxiolysis
- Analgesia
- 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
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