Fig. 2. Analgesia after ulnar nerve block of placebo/vehicle only (n = 5) and amitriptyline at a concentration of 20 mM (n = 9) and bupivacaine at a concentration of 4 mm (n = 4). Blinded subjects were tested at specific time points with a blunt needle at a designated test area versus  a control area on the contralateral hand. The respective visual analog scale (VAS) score was reported to the blinded experimenter. Data are presented as mean ± SEM. Overall significance was determined by analysis of variance for repeated measurements. Post hoc  analysis (pairwise comparison of different concentrations, placebo, or both at each time point) was performed by the Scheffé method. All subjects had normal pain sensation by the next morning. P < 0.05 for placebo versus  20 mM amitriptyline and placebo versus  4 mm bupivacaine.