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 Emergency Medicine Trainee with interests in medical education, ECG interpretation, and the use of point-of-care ultrasound in the undifferentiated patient. Co-author of the LITFL ECG Library | Twitter

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