Interaction between flurazepam and ethanol.

The interaction of a representative benzodiazepine, flurazepam, and ethanol has been assessed in ICR albino mice. Tests done included loss of "rotarod" performance, light sedation, deep sedation, loss of righting reflex, anesthesia, and lethality. LD50 and ED50s were plotted as isobolograms (plots of equieffective dose combinations). Data for anaesthesia and lethality showed little or no interaction between the two drugs. In contrast, the four motor and behaviour tests showed synergism, especially with higher doses of ethanol (over 2 g/kg) for righting reflex, and (over 1.5 g/kg) for deep sedation. Synergism occurred over all doses for light sedation and rotarod performance. It is expected that concurrent use of benzodiazepines and ethanol can result in a significantly higher accident risk in humans, but little additional risk of death from simple overdose.