Which of the following is categorized as a short-acting barbiturate?

Secobarbital is categorized as a short-acting barbiturate due to its pharmacokinetic properties, which include a relatively quick onset of action and a shorter duration of effects compared to other barbiturates. This makes it particularly useful in medical settings for inducing sleep or managing anxiety temporarily.

Short-acting barbiturates, like secobarbital, typically have half-lives that allow for rapid metabolism and elimination from the body, making them suitable for short-term treatments. In the context of the other choices, phenobarbital is classified as a long-acting barbiturate, while amobarbital and mephobarbital are considered intermediate-acting. Understanding these classifications is crucial in clinical settings to ensure that the appropriate type of barbiturate is used for specific therapeutic needs.