Sedative-Hypnotic Drugs Benzodiazepines: - Bind to specific GABAA receptor subunits at central nervous system (CNS) neuronal synapses facilitating GABA-mediated chloride ion channel opening frequency • enhance membrane hyperpolarization - Dose-dependent depressant effects on the CNS including sedation and relief of anxiety • amnesia • hypnosis • anesthesia • coma • and respiratory depression Barbituates: - Bind to specific GABA-A receptor subunits at CNS neuronal synapses facilitating GABA-mediated chloride ion channel duration • enhance membrane hyperpolarization - Dose-dependent depressant effects on the CNS including sedation and relief of anxiety • amnesia • hypnosis • anesthesia • coma and respiratory depression • dose-response relationship than Newer Hyponotics: - Bind selectively to a subgroup of GABAA receptors, acting like benzodiazepines to enhance membrane hyperpolarization - Rapid onset of hypnosis with few amnestic effects or day-after psychomotor depression or somnolence Melatonin Receptor Antagonists: - Activates MT1 and MT2 receptors in suprachiasmatic nuclei in the CNS - Rapid onset of sleep with minimal rebound insomnia or withdrawal symptoms Orexin Antagonists: - Blocks binding of orexins, neuropeptides that promote wakefulness - Promotes sleep onset and duration 5-HT-Receptor Agonist: Mechanism uncertain: - Partial agonist at 5-HT receptors but affinity for receptors also possible - Slow onset (1-2 weeks) of anxiolytic effects • minimal psychomotor impairment—no additive CNS depression with sedative-hypnotic drugs #Sedative #Hypnotic #Drugs #medications #pharmacology #comparison #table
