Benzodiazepines: Pharmacological Effects

• Those compounds that bind and enhance the inhibitory actions of GABA are complete agonists

  • ^(Ex) Lorazepam, midazolam, etc.

• Those compounds that bind with “less than complete agonist action” are termed partial agonists

  • ^(Ex) Ambien (zolpidem)

• Those compounds that bind and decrease the inhibitory actions of GABA are inverse agonists

• Those compounds that bind and have no effect on GABA inhibition are antagonists

  • Prevent enhancement of GABA effects, but do NOT reduce the basal conductance of Cl^-

  • Prevent gating of Cl^- channels in spite of the presence of benzodiazepines

  • Flumazenil (a benzodiazepine) binds with high affinity to the GABA_A complex, but elicits no response

    • Rapidly metabolized in the liver, and therefore has a very short half-life

Category: Pharmacology Notes