The Effects of Stacked Triazolam Dosing on Memory and Suggestibility

To address high levels of anxiety about dental care, anesthesia and sedation medication use by non-anesthesiologists, including dentists, has increased. The amnesiac effect of benzodiazepines on explicit memory is well documented. Effects on suggestibility and implicit memory are less clear. Objectives: This study evaluated the hypothesis that stacked dosing of the benzodiazepine triazolam (Halcion®) prevents both explicit and implicit learning in a dose-related manner. Methods: Forty-six healthy adults 21-39 years, not receiving dental treatment, were randomly assigned to either the placebo (n=12) or 1-of-3 oral sublingual triazolam dosing groups (0.25mg, n=10; 0.5mg stacked over 60 minutes, n=11; or 0.75mg stacked over 90 minutes, n=13). Amnesia and suggestibility memory tasks were administered at pre-determined times after triazolam administration. Subjects were shown pictures, read two word lists and told to remember them for a later memory test. Two hours after the first dose of triazolam or placebo was administered, false information about a previously learned event was provided in order to assess suggestibility levels. Memory was measured the following day using recall and recognition tasks. Results: As hypothesized, compared to the placebo, all triazolam dosing paradigms produced decreased levels of explicit memory performance that were dose-dependent. However, implicit memory performance with 0.25mg was not significantly different from the placebo group. The combined 0.25 mg and placebo groups were different from the 0.5 and 0.75 mg groups. Additionally, placebo participants accepted the false information, whereas those in the drug conditions failed to do so (p=.039). Conclusions: Results suggest that profound amnesia occurs with stacked doses of triazolam above 0.25mg. Single and stacked doses of triazolam decrease vulnerability to misinformation. Dentists using stacked dosing of triazolam need to make allowances for how amnesia will impact their patients during their recovery from sedation. Supported by NIDCR/NIH grants DE0142541, T32DE07132 and Aspect Medical Systems, Newton, MA.