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Midazolam

Class
Indications
Administration/Absorption
  • Intravenous midazolam is indicated for procedural sedation (often in combination with an opioid, such as fentanyl)
  • Oral
    • poorly absorbed orally with only 50 percent of the drug reaching the bloodstream
Dosage

Distribution

Mechanism
  • Benzodiazepines bind at the interface of the α and γ subunits on the GABAA receptor
    • Requires that alpha subunits contain a histidine amino acid residue, (i.e., α1, α2, α3 and α5 containing GABAA receptors)
    • Benzodiazepines show no affinity for GABAA receptors containing α4 and α6 subunits with an arginine instead of a histidine residue.[118]
  • Benzodiazepine ligand locks the benzodiazepine receptor into a conformation in which it has a greater affinity for the GABA neurotransmitter
  • This increases the frequency of the opening of the associated chloride ion channel and hyperpolarizes the membrane of the associated neuron
  • The inhibitory effect of the available GABA is potentiated, leading to sedatory and anxiolytic effects.
Excretion
  • short-acting benzodiazepine in adults with an elimination half-life of one to four hours
  • Midazolam is metabolised into an active metabolite alpha1-hydroxymidazolam
    • However, the active metabolite of midazolam is minor and contributes to only 10 percent of biological activity of midazolam.
  • Metabolised by cytochrome P450 (CYP) enzymes and by glucuronide conjugation
Side effects

Interactions

Contraindications

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