For a client experiencing insomnia, which of the following medications would be most appropriate?

Zolpidem is specifically designed to address sleep disturbances such as insomnia. It belongs to a class of medications known as sedative-hypnotics, and it works by enhancing the effects of a neurotransmitter in the brain called gamma-aminobutyric acid (GABA), which promotes relaxation and sleep. This makes it particularly effective for short-term management of insomnia symptoms, helping clients fall asleep more quickly and improve overall sleep duration and quality.

In contrast, other medications listed serve different purposes. Diazepam, while it does possess sedative effects, is primarily an anxiolytic and muscle relaxant that can lead to dependence if used long-term for insomnia. Sertraline is an antidepressant in the selective serotonin reuptake inhibitor (SSRI) class, which is not indicated specifically for treating insomnia and may have stimulating effects. Buspirone is an anxiolytic that can help with anxiety but is not typically used for treating sleep disorders. Therefore, for a client experiencing insomnia, Zolpidem is the most appropriate medication choice due to its targeted action on promoting sleep.