Which one of the following is a short-acting hypnotic?

Triazolam is considered a short-acting hypnotic primarily because of its pharmacokinetic profile, specifically its relatively quick onset and short duration of action. This characteristic makes it particularly useful for the treatment of insomnia, especially for patients who have difficulty falling asleep.

Triazolam quickly generates its sedative effects, generally within 15-30 minutes of ingestion, and its effects taper off within a matter of hours, reducing the likelihood of next-day sedation or impairment, which is often a concern with longer-acting hypnotics. Short-acting hypnotics like triazolam are favored in situations where rapid onset of sleep is desired without prolonged sedation.

In contrast, the other options listed—phenobarbital, diazepam, and chlordiazepoxide—are classified differently. Phenobarbital is a long-acting barbiturate that can be used for seizure disorders as well as for its sedative properties but is not typically used as a short-acting hypnotic. Diazepam and chlordiazepoxide are benzodiazepines but are also longer-acting compared to triazolam and are often used for anxiety or muscle relaxation rather than as a primary treatment for insomnia. Thus, triazolam