Pharm

Dexmedetomidine

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Dexmedetomidine, Precedex, Dexdor, Dexdomitor

  • Indications
  1. Post-Intubation Sedation and Analgesia
    1. Short-term sedation (<24 hours) in ICU patients on Mechanical Ventilation
    2. Tachyphylaxis occurs with use >24 hours
  2. Noninvasive Positive Pressure Ventilation or NIPPV (e.g. BIPAP)
    1. Dexmedetomidine may help patients tolerate the NIPPV mask
  3. Other patients requiring sedation
    1. Alcohol Withdrawal
    2. Peri-procedure sedation
    3. Neurocritical care patients
    4. Tachycardic patients on Vasopressors
  • Contraindications
  1. Severe Bradycardia
  • Mechanism
  1. Selective central alpha-2-adrenergic agonist (similar to Clonidine) with sedative properties
    1. Lacks the peripheral effects on vascular resistance of Clonidine
    2. However, sedation effect is maintained
  2. Brainstem G-Protein activation inhibits Norepinephrine release
    1. Decreases sympathetic tone and peripheral vascular resistance
  • Advantages
  1. Keeps a patient sleepy but awakenable and will respond to questions
  2. Patients maintain their wairway and respiratory drive
  3. Generic (previously very expensive as a trade name drug)
  4. Opioid sparing (offers sedation and Analgesic properties)
  • Pharmacokinetics
  1. Onset: 10 minutes
  2. Duration: 1-2 hours
  3. Renal and hepatic metabolism
  1. Load: 1 mcg/kg in adults (0.5 to 1 mcg/kg in children) over 10 minutes, then
    1. Precaution: Bolus may result in Hypotension
  2. Infusion: 0.2 to 0.7 mcg/kg/hour in adults (0.2 to 0.5 mcg in children)
    1. Titrate to desired level of sedation, modifying dose every 30 min to 0.2 to 1.5 mcg/kg/hour
    2. Decrease dosing in hepatic dysfunction and the elderly
  3. Reduce dose in over age 65 years or renal/hepatic Impairment
  • Dosing
  • Post-Intubation Sedation
  1. Another sedative (e.g. Propofol or Ketamine) should be used initially to maintain initial sedation
  2. Start Dexmedetomidine at 0.5 mcg/kg/h infusion
  3. Increase Dexmedetomidine by 0.1 mcg/kg/h as needed up to 1.5 mcg/kg/h
  • Adverse Effects
  1. Severe Bradycardia
    1. If Heart Rate drops below minimum threshold, stop infusion for 30 min, and restart at 1/2 prior rate
  2. Hypotension
    1. Transient Hypertension may occur with rapid infusion or bolus
  3. Dry Mouth
  4. Potent Diuretic
  • References
  1. Swaminathan and Weingart in Herbert (2019) EM:Rap 19(6): 14
  2. Fisher and Fisher (2018) Crit Dec Emerg Med 32(1): 24
  3. Kay (2015) Crit Dec Emerg Med 29(8): 11-17