sedative

Midazolam

Versed

Route: IV · IM · IN (intranasal) · oral · buccal
Onset: 2–3 minutes (IV)
Duration: 1–6 hours (longer with accumulation)

Mechanism of action

Benzodiazepine. Positive allosteric modulator of GABA-A receptors → enhances chloride influx → CNS depression. Provides anxiolysis, sedation, amnesia, and anticonvulsant effects. No analgesic properties.

Dosing

Adult: ICU sedation: 0.01–0.1 mg/kg/hr continuous infusion. Procedural: 0.5–2 mg IV increments
Pediatric: Sedation: 0.05–0.1 mg/kg IV q2h PRN or 0.06–0.12 mg/kg/hr infusion

Indications

ICU sedation (continuous infusion)
Procedural sedation / conscious sedation
Premedication before procedures
Alcohol withdrawal seizures
Status epilepticus
RSI co-induction (with ketamine or propofol)

Contraindications

Acute narrow-angle glaucoma
Hypersensitivity to benzodiazepines
Severe hepatic impairment (active metabolite accumulates)

Side effects

Respiratory depression (dose-dependent)
Hypotension
Paradoxical excitation (children and elderly)
Amnesia (therapeutic but can cause patient distress)
Accumulation with prolonged infusion (active metabolite 1-OH-midazolam)

Monitoring parameters

RASS or Ramsay Sedation Scale
Respiratory rate and SpO2
Blood pressure
Accumulation signs (prolonged sedation after dose reduction)
Flumazenil availability (reversal agent)

Drug interactions

CNS depressants (additive respiratory depression)
CYP3A4 inhibitors (increase midazolam levels — prolonged sedation)
Flumazenil (reversal agent)
Opioids (additive respiratory depression — combined with fentanyl for ICU sedation)

NBRC high-yield

Benzodiazepine — sedation, anxiolysis, amnesia; NO analgesia
Reversal: flumazenil (0.2 mg IV)
Active metabolite accumulates in renal failure
Respiratory depression potentiated with opioids
Context-sensitive half-life increases with prolonged infusion

Clinical pearls

Reversal: flumazenil (0.2 mg IV; repeat q1 min × 5 doses; max 1 mg)
Active metabolite (1-OH-midazolam) accumulates in renal failure → prolonged sedation
Prolonged infusion can lead to tolerance and withdrawal — wean gradually
Causes amnesia (retrograde and anterograde) — frequently used for procedures
Not an analgesic — combine with opioid for pain management in ventilated patients
Context-sensitive half-life increases with prolonged infusion (accumulates in fat)

Mnemonic

Midazolam: Marshmallow (soft, fuzzy sedation) — but context-sensitive accumulation

All Drugs

Clinical pearls

Reversal: flumazenil (0.2 mg IV; repeat q1 min × 5 doses; max 1 mg)

Active metabolite (1-OH-midazolam) accumulates in renal failure → prolonged sedation

Prolonged infusion can lead to tolerance and withdrawal — wean gradually

Causes amnesia (retrograde and anterograde) — frequently used for procedures

Not an analgesic — combine with opioid for pain management in ventilated patients

Context-sensitive half-life increases with prolonged infusion (accumulates in fat)