Pharm 101: Clonazepam



  • 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
  • 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 CCPU (RCE, Biliary, DVT, E-FAST, AAA) Rob is an Emergency Medicine Advanced Trainee based in Melbourne, Australia. He has special interests in medical education, ECG interpretation, and the use of diagnostic and procedural ultrasound in the undifferentiated and unwell patient.

Follow him on twitter: @rob_buttner | ECG Library |

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