Which Z-drug has the shortest half-life and is commonly used for sleep onset insomnia?

• A. Zaleplon
• B. Zolpidem
• C. Eszopiclone
• D. Ramelteon

Answer: (A)

The key idea is matching a drug’s duration in the body to the specific sleep problem. For sleep onset insomnia, you want something that acts fast but clears quickly to reduce next-day drowsiness. Zaleplon has the shortest half-life among the Z-drugs—about one hour—so it quickly helps you fall asleep and largely wears off by the next day. The other Z-drugs last longer (zolpidem and eszopiclone) and can leave you with residual sedation or affect sleep maintenance rather than onset. Ramelteon isn’t a Z-drug at all; it’s a melatonin receptor agonist with a different pharmacologic profile, so it’s not the best fit when the question focuses on the shortest-acting option for sleep onset.