Author: Mr. Satyendra Garg
Volume: 01
First Online: 31 August 2024
Pages: 164-176
DOI:

Sedatives and hypnotics are drugs that depress the central nervous system (CNS) to induce calmness (sedation) or promote sleep (hypnosis). These agents are classified into several categories, including benzodiazepines, barbiturates, and newer non-benzodiazepine hypnotics. The mechanism of action typically involves enhancing the inhibitory neurotransmitter gamma-aminobutyric acid (GABA) at the GABA-A receptor, increasing neuronal inhibition and producing sedative or hypnotic effects. Benzodiazepines, such as chlordiazepoxide, diazepam, oxazepam, chlorazepate, lorazepam, and alprazolam, bind to specific sites on the GABA-A receptor, enhancing GABA’s effect and resulting in sedative, anxiolytic, muscle relaxant, and anticonvulsant properties. These drugs are commonly used to manage anxiety disorders, insomnia, seizures, and muscle spasms. The structure-activity relationship (SAR) of benzodiazepines reveals that the presence of a benzene ring fused to a diazepine ring, along with specific substitutions, influences their potency, duration of action, and receptor affinity. For instance, diazepam is widely used for its rapid onset and long duration of action, while lorazepam and oxazepam are preferred for patients with liver impairment due to their simpler metabolism. Zolpidem, a non-benzodiazepine hypnotic, selectively binds to the benzodiazepine receptor subtype, offering effective sleep induction with fewer side effects. Understanding the SAR helps in designing sedatives and hypnotics with desired therapeutic profiles and minimized adverse effects.