UNCONTROLLED WHEN PRINTED

Introduction

  • A water-soluble benzodiazepine that has anxiolytic, sedative and anticonvulsive characteristics. These are based on its bond with receptors in the central nervous system; 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 central nervous system quickly.

    Pharmacokinetics

    Onset

    • Rapid onset

    Absorption

    • Aafter IM injection, absorption from the muscle tissue is rapid and complete. Maximum plasma concentrations are reached within 30 minutes. The absolute bioavailability after IM injections is over 90%.

    Excretion

    • 60-80% of the dose is excreted in urine as conjugates

    Pharmacodynamics

    Desired Effects

    • Midazolam is a very short-acting benzodiazepine, with powerful anxiolytic, sedative-hypnotic and muscle relaxant effects caused by facilitation of GABA-mediated CNS inhibitory pathways.
    • It has rapid onset of actions and, because of rapid metabolic transformation, short duration.

    Side Effects

    • Respiratory depression.
    • Hypotension.
    • Anterograde and retrograde amnesia.

    Duration of Action:

    • Very short acting.

    Half-life

    • 1 to 3 hours

    Other Drug Interactions

    • Midazolam has additive CNS-depressant effects with all other CNS depressants.

    Page contributors:

    DefaultDefault Author
    St John WA
    Want to help improve this article? Visit our Contribute page.

    St John Ambulance Western Australia Ltd © Copyright 2020, All Rights Reserved

    Privacy Policy | Copyright Statement & Disclaimer