Zolpidem is a non-benzodiazepine hypnotic that acts on GABA-A receptors. Compared to diazepam, zolpidem's selectivity is explained by its preferential binding to:

• A GABA-A receptors containing the alpha-2 and alpha-3 subunits (anxiolytic subtype)
• B GABA-B receptors in the thalamus, distinct from benzodiazepine binding sites
• C GABA-A receptors containing the alpha-1 subunit (sedative subtype), with minimal alpha-2/alpha-3 binding ✓
• D Benzodiazepine omega-2 receptors in the spinal cord, producing muscle relaxation

Explanation

Zolpidem selectively binds GABA-A receptors containing the alpha-1 subunit (classified as benzodiazepine BZ1/omega-1 receptors), which mediate sedation, amnesia, and anticonvulsant effects; this subunit selectivity explains its hypnotic efficacy with minimal anxiolytic and muscle-relaxant activity compared to non-selective benzodiazepines. Alpha-2 and alpha-3 subunit-containing receptors mediate anxiolysis and muscle relaxation. Benzodiazepines bind all alpha subunits (alpha-1, 2, 3, 5) non-selectively.

Reference: KD Tripathi, Essentials of Medical Pharmacology, 8th ed.

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Written and medically reviewed by the StethoPrep medical team.