• A water-soluble benzodiazepine that has anxiolytic, sedative and anticonvulsive characteristics. This is due to its bonding with receptors in the CNS; its action to increase the inhibitory effect of the g-aminobutyric acid (GABA) neurotransmitter on the GABA receptors and subsequent membrane threshold.
  • Midazolam is lipid-soluble in physiological pH and it reaches the CNS quickly.
  • Use of a sedative agent should never be considered routine. Have a high threshold to offer or administer.

Pharmacology Review

  • Prolonged seizure activity - generalised seizure lasting ≥ 5 minutes OR recurrent / status seizure activity as per CPG
  • Focal seizure activity which is prolonged (≥ 5 minutes) and is associated with a GCS ≤ 12 as per CPG
  • Second-line IV agent for maintenance of sedation after Droperidol administration for Disturbed and/or Abnormal Behaviour
Critical Care
  • For the purpose of providing and maintaining procedural sedation
  • Hypersensitivity
  • Use of Midazolam for sedation after Ketamine requires ASMA authority
 Precautions / Notes
  • Early monitoring as soon as practicable is required when administering midazolam; including SpO2, respiratory rate, pulse and blood pressure
  • SpO2 and EtCO2 monitoring must be applied whenever level of consciousness drops consistent with the Sedative Warnings section below.
  • Psychostimulants, in toxic levels can produce severe agitation and psychotic behaviour
  • Paediatric patients:
    • Intramuscular administrations should always be prepared in a 1mL IM syringe
    • Have a low threshold to consult with ASMA when repeat or maintenance doses are required for sedation
Sedation warnings
  • Sedation is HIGH RISK – must only be carried out after careful deliberation between officers and must not be based primarily at the request or influence of other agencies on scene (e.g. Police etc.)
  • Positive RASS score does not automatically infer a need to sedate
  • Age <16 years old – sedation should prompt a prior ASMA consult wherever practicable
  • ETOH / Intoxication – apply caution
  • Repeat & Maintenance doses – have a low threshold to consult with ASMA where repeat or maintenance doses are required
  • Monitoring – SpO2 and EtCO2 monitoring must be applied whenever level of consciousness drops (~RASS -2 or below)
  • Positioning – DO NOT transport in supine position (increases risk of laryngospasm from secretions) – transport in lateral position
  • Airway & Breathing – monitor airway and breathing effort, including chest movement closely for signs of impairment. Prepare to support if required
  • Restraint – Prone and/or handcuffed to rear carries excessive risk and MUST NOT occur. Physical restraint in any position that amplifies the risk of positional asphyxia, must be closely observed for signs of air hunger and hypoxia
  • RASS scores must be agreed and documented
  • Weight – Estimated weight must be agreed before administration of any weight based medicines. This must be documented

The final decision to sedate lies with the most senior clinician on scene



  • Do NOT dilute in general


  • Dilute 15 mg / 3 ml with 12 ml NaCl in 20 ml syringe (equivalent to 1 mg/ml)
  • Part dilution into a 10 ml syringe is no longer advocated
 Weight-based Calculations
IV Midazolam for Seizures
Presentation: 15mg:15mL
 to 5mg in  to 5mL
IM Midazolam for Seizures
Presentation: 15mg:3mL
IV Midazolam for Maintenance of Sedation
Presentation: 15mg:15mL
 to  in  to


Adult < 70 years:

  • IM
    • Initial dose: 5 mg 
    • Subsequent dose: 5 mg repeat once after 10 min if needed and no IV access.
  • IV/IO
    • Initial dose: 2.5 - 5 mg
    • Subsequent dose: 2.5 mg every 5 min as needed to 15 mg max total.

Adult ≥ 70 years or frail:

  • IM
    • Initial dose: 2.5 mg
    • Subsequent dose: 2.5 mg repeat once after 10 min if required and no IV access.
  • IV/IO
    • Initial dose: 2.5 mg
    • Subsequent dose: 1 mg every 5 min as needed to 15 mg max total.


  • IM
    • Initial dose: 0.2 mg/kg (max single bolus 5 mg)
    • Subsequent dose: repeat initial dose once after 10 min if needed and no IV access.
  • IV/IO
    • Initial dose: 0.1 mg/kg (max single bolus dose of 2.5 mg)
    • Subsequent dose: repeat initial dose as needed every 5 min to 10 mg max total.

The use of Midazolam in both adults and paediatric patients for other seizure types outside of CPG requires ASMA authority.

Maintenance of Sedation (IV Only)
Administration limited to those with independent authority to practice per the Medications Schedule 

Adult < 70 years of age:

  • IV
    • 1 - 2 mg, titrated to effect every 5 - 10 mins as required to a total max dose 5 mg

Adult ≥ 70 years or frail:

  • IV
    • 0.5 - 1 mg, titrated to effect every 5 - 10 mins as required to a total max dose 5 mg

Paediatric (6-15 years of age):

  • IV
    • 0.5 mg - 1 mg, titrated to effect every 5 - 10 mins as required to a total max dose 5 mg
 Special Considerations
  • Respiratory depression
  • Hypotension
  • Anterograde and retrograde amnesia
  • Myasthenia Gravis
15 mg in 3 ml (5 mg/ml)
Current mode:
Extended Care:
Colour assist:

Discarding unused medication must be witnessed and countersigned by attendant and credible witness.


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Head of Clinical Services


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