Triazolam is a benzodiazepine with a very short elimination half-life (about 3 hours).

In sleep laboratory studies in man of 1 to 21 days duration, triazolam reduced sleep latency, increased duration of sleep and decreased the number of nocturnal awakenings. However, after 2 weeks of consecutive nightly administration, the drug's effect on total wake time is decreased, and the values recorded in the last third of the night approach baseline levels. On the first and/or second night after drug discontinuance (first or second post-drug night), total time asleep, and percentage of time spent sleeping frequently were significantly decreased, and sleep latency significantly increased when compared to baseline (predrug) nights. This effect is often called "rebound" insomnia.

The duration of hypnotic effect and the profile of unwanted effects may be influenced by the alpha (distribution) and beta (elimination) half-lives of the administered drug and any active metabolites formed. When half-lives are long, the drug or metabolites may accumulate during periods of nightly administration and be associated with impairments of cognitive and motor performance during waking hours. If half-lives are short, the drug and metabolites will be cleared before the next dose is ingested, and carry-over effects related to sedation or CNS depression should be minimal or absent. However, during nightly use and for an extended period, pharmacodynamic tolerance or adaptation to some effects of benzodiazepine hypnotics may develop. If the drug has a very short elimination half-life, it is possible that a relative deficiency (i.e., in relation to the receptor site) may occur at some point in the interval between each night's use. This sequence of events may account for two clinical findings reported to occur after several weeks of nightly use of rapidly eliminated benzodiazepine hypnotics: (1) increased wakefulness during the last third of the night and (2) the appearance of increased day-time anxiety (see Warnings).