Effects of acute and chronic alprazolam treatment on cerebral blood flow, memory, sedation, and plasma catecholamines.

The effects of 0.014 mg/kg intravenous alprazolam administration on cerebral blood flow (CBF), memory, sedation, and plasma norepinephrine and epinephrine were determined in eight healthy males at baseline levels and following 1 week of daily oral alprazolam treatment. At baseline, intravenous alprazolam administration caused acute reductions in whole-brain CBF (25% to 30% decrease), memory, plasma epinephrine, and self-rated alertness. Following 1 week of alprazolam treatment, tolerance developed to the acute effects of intravenous alprazolam on CBF, memory, and plasma epinephrine. There were no consistent regional neuroanatomic differences in the CBF effects of acute alprazolam, or in the development of tolerance to these effects, and no correlations between the various measures of acute alprazolam effects on either test day.