sedative

Dexmedetomidine

Precedex

Route: IV
Onset: 5–10 minutes
Duration: Continuous infusion; short offset after stopping

Mechanism of action

Selective alpha-2 adrenergic agonist. Activates central (locus coeruleus) alpha-2 receptors → decreased norepinephrine release → sedation and anxiolysis. Peripheral alpha-2 activation → decreased sympathetic outflow and pain signal transmission.

Dosing

Adult: ICU: 0.2–0.7 mcg/kg/hr (no loading dose typically in ICU). Procedural: loading dose 0.5–1 mcg/kg over 10 min, then 0.2–0.7 mcg/kg/hr

FDA-approved for up to 24 hours; commonly used longer off-label

Indications

ICU sedation for mechanically ventilated patients
Procedural sedation
Adjunct to facilitate extubation
Alcohol withdrawal adjunct

Contraindications

Advanced heart block (without pacemaker)
Severe bradycardia
Hypersensitivity to dexmedetomidine

Side effects

Bradycardia (most common)
Hypotension
Transient hypertension with loading dose (initial alpha-1 stimulation)
Dry mouth
Nausea

Monitoring parameters

Heart rate and BP continuously
RASS scale
SpO2
ECG for bradycardia / AV block

Drug interactions

Beta-blockers (additive bradycardia and hypotension)
Other antihypertensives (additive hypotension)
Digoxin (additive bradycardia)

NBRC high-yield

Alpha-2 agonist — cooperative, rousable sedation
Does NOT cause respiratory depression (key advantage)
Side effects: bradycardia and hypotension
Reduces delirium vs. benzodiazepines (MENDS/SEDCOM trials)
Useful for extubation facilitation
Avoid in high-degree AV block

Clinical pearls

Unique: allows rousable, cooperative sedation — patients can follow commands and communicate
Does NOT cause significant respiratory depression — patient can maintain airway and ventilate
Reduces opioid and benzodiazepine requirements
MENDS and SEDCOM trials: less delirium than benzodiazepines
Excellent for facilitating extubation — patient remains cooperative during weaning
Withdrawal syndrome with abrupt discontinuation after prolonged use (hypertension, tachycardia)

Mnemonic

Precedex = Patients can still talk (cooperative sedation), no respiratory depression

All Drugs

Clinical pearls

Unique: allows rousable, cooperative sedation — patients can follow commands and communicate

Does NOT cause significant respiratory depression — patient can maintain airway and ventilate

Reduces opioid and benzodiazepine requirements

MENDS and SEDCOM trials: less delirium than benzodiazepines

Excellent for facilitating extubation — patient remains cooperative during weaning

Withdrawal syndrome with abrupt discontinuation after prolonged use (hypertension, tachycardia)