Dexmedetomidine
Precedex
Selective α2-adrenergic agonist
α2 agonist (locus coeruleus) → sedation + analgesia + anxiolysis without significant respiratory depression.
Indications
- •ICU sedation
- •Awake fiberoptic intubation
- •Procedural sedation
- •Adjunct for emergence delirium prevention
- •Opioid-sparing analgesia
Dosing
| Context | Adult | Pediatric |
|---|---|---|
| Loading | 1 mcg/kg over 10 min (often skipped to avoid hypotension) | — |
| Maintenance | 0.2–0.7 mcg/kg/hr | — |
| Procedural | 0.5–1 mcg/kg load, 0.5–1 mcg/kg/hr | — |
Pharmacokinetics
Onset 5–10 min. Hepatic CYP. Half-life 2 h.
Hemodynamic effects
Biphasic: transient ↑BP at load (peripheral α2B vasoconstriction) → sustained ↓HR + ↓BP. Bradycardia frequent.
Respiratory effects
Minimal — preserved spontaneous ventilation, the key advantage.
Side effects
- !Bradycardia (sometimes profound, especially with vagotonic stimuli)
- !Hypotension
- !Withdrawal HTN if abrupt stop after long infusion
Contraindications
- ×Advanced heart block without pacer
- ×Severe LV dysfunction (relative)
Clinical pearls
- ★Skip the load if patient is already hypotensive.
- ★Lower MAC: dex 0.4 mcg/kg/hr lowers volatile MAC ~25%.
- ★Useful for awake intubation: patient cooperative, breathes spontaneously, less coughing.
Education only — confirm against current package inserts and institutional protocols. Doses assume normal organ function unless otherwise noted.