Triazolam and phase-shifting acceleration re-evaluated.

In two experiments, triazolam (2.5 and 1.5 mg/animal) failed to significantly enhance the rate of reentrainment of hamsters (Mesocricetus auratus) to an 8-hr advance of their light-dark cycle. Evidently the phase-shifting effects of triazolam are not robust. The animals did not run much in their wheels in response to the drug in these two experiments. In a third experiment, triazolam (0.5 and 2.5 mg/animal) produced phase advances of activity rhythms of hamsters in the dark. In this experiment, running in response to the drug was greater. Hamsters given triazolam but confined to their nest boxes over the next few hours did not show phase shifts. The phase-shifting effects of triazolam (when they do occur) appear to be mediated through activity increases. Triazolam-treated hamsters became ataxic in all three of these experiments. Suggestions that triazolam may be useful in ameliorating rhythm disturbances in people should be treated with a caution.