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Dexmedetomidine
Aka: Dexmedetomidine, Precedex, Dexdor, Dexdomitor
- Indications
- Post-Intubation Sedation and Analgesia
- Use other agents (e.g. Propofol) in the first hour after intubation (delayed effect with Dexmedetomidine)
- Short-term sedation and weaning (<24 hours up to 4-5 days) in ICU patients on Mechanical Ventilation
- Tachyphylaxis occurs with use >24 hours and esp. >4-5 days
- Noninvasive Positive Pressure Ventilation or NIPPV (e.g. BIPAP)
- Dexmedetomidine may help patients tolerate the NIPPV mask
- Other patients requiring sedation
- Alcohol Withdrawal
- Peri-procedure sedation
- Neurocritical care patients
- Tachycardic patients on Vasopressors
- Contraindications
- Severe Bradycardia
- Hemodynamically unstable (significant Hypotension)
- Mechanism
- Selective central alpha-2-Adrenergic Agonist (similar to Clonidine) with Sedative properties
- Lacks the peripheral effects on vascular resistance of Clonidine
- However, sedation effect is maintained
- Brainstem G-Protein activation inhibits Norepinephrine release
- Decreases sympathetic tone and Peripheral Vascular Resistance
- Advantages
- Keeps a patient sleepy but awakenable and will respond to questions
- Patients maintain their airway and respiratory drive (ideal for Mechanical Ventilation weaning)
- Generic (previously very expensive as a trade name drug)
- Opioid sparing (offers sedation and Analgesic properties)
- Pharmacokinetics
- Onset: 10 minutes
- Duration: 1-2 hours
- Renal and hepatic metabolism
- Dosing: General
- Load
- Option 1: Infuse 1 mcg/kg in adults (0.5 to 1 mcg/kg in children) over 10 minutes OR
- Precaution: Bolus may result in Bradycardia and Hypotension
- Option 2: Start high dose infusion 1 to 1.4 mcg/kg/hour without bolus
- Decrease infusion rate in the first 30-60 minutes to maintenance infusion
- Infusion: 0.2 to 0.7 mcg/kg/hour in adults (0.2 to 0.5 mcg in children)
- Titrate to desired level of sedation, modifying dose every 30 min to 0.2 to 1.5 mcg/kg/hour
- Decrease dosing in hepatic dysfunction and the elderly
- Reduce dose in over age 65 years or renal/hepatic Impairment
- Dosing: Post-Intubation Sedation
- Another Sedative (e.g. Propofol or Ketamine) should be used initially to maintain initial sedation
- Start Dexmedetomidine at 0.5 mcg/kg/h infusion
- Increase Dexmedetomidine by 0.1 mcg/kg/h as needed up to 1.5 mcg/kg/h
- Dosing: Intranasal for Procedural Sedation
- Dose: 2-3 mcg/kg
- Onset in 13-25 minutes and duration for 85 minutes (longer in adults)
- Intranasal use rarely causes Bradycardia or Syncope
- Oriby (2019) Anesth Pain Med 9(1): e85227 +PMID:30881910 [PubMed]
- Adverse Effects
- Severe Bradycardia
- If Heart Rate drops below minimum threshold, stop infusion for 30 min, and restart at 1/2 prior rate
- Hypotension
- Transient Hypertension may occur with rapid infusion or bolus
- Low dose Epinephrine infusion may be used to counter Dexmedetomidine Bradycardia and Hypotension
- Dry Mouth
- Potent Diuretic
- Tachyphylaxis
- Risk of tolerance (within 4-5 days of starting Dexmedetomidine, as early as 24 hours in some patients)
- Results in less sedation and risk of withdrawal
- Transition to Clonidine if Dexmedetomidine tolerance develops
- References
- Swaminathan and Weingart in Herbert (2019) EM:Rap 19(6): 14
- Fisher and Fisher (2018) Crit Dec Emerg Med 32(1): 24
- Kay (2015) Crit Dec Emerg Med 29(8): 11-17