Midazolam causes less sedation in volunteers with red hair

Abstract

Purpose: We studied sedation, cognition, and mood during midazolam infusion in volunteers with red and non-red (blond or brown) hair, to test the hypothesis that patients with red hair may require more drugs to attain desired levels of sedation. Methods: Twenty red and 19 non-red hair subjects were studied in a randomized, placebo-controlled cross-over design. Subjects were studied during placebo and midazolam at 30 ng·mL-1 target effect site concentration. Sedation was assessed using the observer's assessment of alertness/sedation (OAA/S) scale, the drowsiness visual analogue scale (VAS), and the bispectral index; cognition was assessed using the Repeatable Battery for Assessment of Neuropsychological Status; and mood was assessed using the bipolar form of the Profile of Mood States (POMS). Results: Red hair volunteers showed significantly higher OAA/S (P < 0.01) and lower drowsiness VAS (P < 0.05) scores compared to non-red hair subjects during midazolam infusion. Visuospatial score was significantly higher in subjects with red compared to non-red hair during placebo and midazolam trials. Delayed memory score was significantly higher during midazolam infusion in subjects with red compared to non-red hair. There were no group differences in POMS during either trials. Conclusion: Midazolam appears to cause significantly less sedation and cognitive impairment in red haired subjects.