Pharm

Methohexital

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Methohexital, Methohexital Sodium, Brevital

  • Contraindications
  1. Absolute Contraindications
    1. Acute Intermittent Porphyria
    2. Barbiturates Hypersensitivity
  2. Relative Contraindications
    1. Cardiovascular disease
    2. Hypotension
    3. Respiratory depression or uncontrolled respiratory disease
  1. Close cardiopulmonary monitoring (e.g. Pulse Oximetry, Blood Pressure, End-Tidal CO2)
  2. Airway management (e.g. suction, LMA, Endotracheal Intubation)
  3. Breathing management (e.g. Supplemental Oxygen, Bag Valve Mask)
  • Mechanism
  1. See Barbiturate
  2. Rapid onset, short acting Barbiturate (barbituric acid derivative)
  3. Cerebral Cortex and cerebellar Sedative-Hypnotic
  • Dosing
  1. Procedural Sedation
    1. Start: 1 mg/kg IV
    2. Next: 0.5 mg/kg every 2-5 minutes
  2. Induction
    1. See Rapid Sequence Intubation
    2. Adults: 50-120 mg (mean 70 mg) IV push given as 10 mg (1 ml of 1% solution) every 5 seconds until effect
  • Pharmacokinetics
  1. Half-life: 3-6 hours
  2. Onset
    1. IV: Immediate
    2. IM: 2-10 minutes
    3. PR: 5-15 minutes
  3. Duration
    1. IV: 10-20 minutes
    2. PR: 45 minutes
  4. Metabolism
    1. Slow hepatic metabolism to inactive substances
  5. Excretion
    1. Primarily excreted in urine (minimal excretion in sweat and stool)
  • Adverse Effects
  1. See Barbiturates
  2. See Procedural Sedation
  3. Laryngospasm (rare)
    1. Administering additional Methohexital dose typically stops the laryngospasm
  4. Respiratory Depression or Apnea
  5. Hiccoughs
  6. Hypotension
  • Resources
  • References
  1. LoVecchio (2019) Crit Dec Emerg Med 33(7): 28