Figure 2. Inhaled histamine concentrations inducing a 20% decrease in the forced expiratory volume in 1 s (FEV¹) before and after lidocaine (left), salbutamol (middle), and combined salbutamol and lidocaine (right) administration, respectively. Each pair of symbols represents the response of individual volunteers, whereas the mean response (+/− SD) is shown to the left and to the right of the individual responses. Data are from 60 inhalational challenges with histamine performed on four different days in 15 persons with bronchial hyperreactivity. Lidocaine and salbutamol both significantly increased the histamine threshold compared with placebo, with no statistical difference occurring between lidocaine and salbutamol. The combination of lidocaine and salbutamol also significantly increased the histamine threshold, but markedly more than lidocaine (P = 0.0007) or salbutamol (P = 0.0008) alone.