Pharm 101: Clonazepam

Class

Benzodiazepine


Pharmacodynamics
  • Long-acting benzodiazepine
  • Binds to GABA-A:
    • Potentiates GABAergic inhibition through hyperpolarisation
    • Increases frequency of chloride channel opening
    • Acts throughout the brain, but the distribution of different GABA-A receptor isoforms varies across the CNS

Pharmacokinetics
  • Bioavailability > 80%
  • Peak concentrations in 1-4 hours
  • 86% protein bound
  • Lipid soluble and crosses blood brain barrier effectively
  • Extensively metabolised in liver to inactive metabolites
  • Half life 12-56 hours

Clinical uses
  • One of the most potent anticonvulsant agents known:
    • Absence seizures
    • Myoclonic seizures
    • Infantile spasms
  • Sedative-hypnotic
  • Anxiolytic

Adverse effects
  • Sedation, especially on initiation of therapy
  • Toxicity and adverse effects are similar to diazepam

Further Reading

Pharm 101 700

Pharmacology 101

Top 200 drugs

MBBS (UWA) CCPU (RCE, Biliary, DVT, E-FAST, AAA) Emergency Medicine Advanced Trainee in Melbourne, Australia. Special interests in diagnostic and procedural ultrasound, medical education, and ECG interpretation. Editor-in-chief of the LITFL ECG Library. Twitter: @rob_buttner

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