GABA-A receptor pharmacology of benzodiazepines and Z-drugs
How benzodiazepines and Z-drugs modulate the GABA-A receptor, why they have a ceiling that barbiturates and alcohol lack, how subunits map to effects, and the pharmacokinetic differences (oxidation versus glucuronidation, lipid solubility, active metabolites) that decide drug choice in liver disease, older people and overdose.
Tier 2Medical sciences concept
Written with AI assistance and fact-checked against the sources below. For exam study, not clinical decisions. How notes are made
At a glance
- Benzodiazepines are positive allosteric modulators of the GABA-A receptor. They increase the frequency of chloride channel opening but need GABA to be present, so on their own they have a ceiling effect.
- Z-drugs (zolpidem, zopiclone) are chemically different but bind the same site; zolpidem is relatively alpha-1 selective. Flumazenil reverses both.
- Choice of drug is mostly pharmacokinetic: lipid solubility (speed of onset, redistribution), route of metabolism (CYP oxidation versus glucuronidation) and active metabolites.
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Sources
- Therapeutic Guidelines: PsychotropicAU/NZTherapeutic Guidelines Ltd, 2021
- Australian Medicines HandbookAU/NZAustralian Medicines Handbook Pty Ltd, 2026
- Benzodiazepines: how they work and how to withdraw (the Ashton Manual)Ashton H, Newcastle University, 2002
- Goodman & Gilman's The Pharmacological Basis of Therapeutics (14th ed.)McGraw Hill (Brunton and Knollmann, 2023), 2023
- Last updated
- 14 November 2026
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