Anticipatory anxiety in moderately to highly-anxious oral surgery patients as a screening model for anxiolytics: evaluation of alprazolam.

Alprazolam, a benzodiazepine anxiolytic, was evaluated in anxious patients prior to oral surgery. This population represents a possible acute screening model for novel anxiolytic agents. Healthy subjects, preselected for a moderate to high degree of dental anxiety based upon Corah's Dental Anxiety Scale, were enrolled in a three-arm parallel design study and randomly assigned to receive double-blind placebo (N=15), alprazolam 0.25 mg (N=16) or alprazolam 1 mg (N=16). Subjective self-reported anxiety was rated using the State Anxiety Inventory and visual analog scales. Objective measures included galvanic skin conductance, heart rate variability, blood pressure, pulse rate, and respiration. At 90 minutes after dosing, there were statistically significant (p<0.05) reductions compared with placebo in subjective anxiety and skin conductance mean level for the alprazolam-treated subjects. Changes from pre-dose (mean +/- SEM) at 90 minutes in the placebo, alprazolam 0.25 mg, and alprazolam 1 mg groups were -4.73 +/- 2.79, -13.75 +/- 2.49, and -12.81 +/- 2.32 for the State Anxiety Inventory and 5.44 +/- 6.71, -31.88 +/- 5.88, and -32.34 +/- 5.32 mm for analog anxiety scores. Corresponding skin conductance mean level at 100 minutes in the three groups (respectively) changed 0.64 +/- 0.24, -0.53 +/- 0.21, -0.71 +/- 0.22 microSiemens. The 0.25 mg and 1 mg dosages of alprazolam were not differentiated. Changes in heart rate variability, blood pressure, pulse rate, and respiration did not reflect subjective anxiety. Overall, the oral surgery anticipation anxiety model was found to be a sensitive test for benzodiazepine anxiolytic activity and may represent a potential screening model for evaluation of investigational agents.