Lidocaine-induced bronchoconstriction in asthmatic patients. Relation to histamine airway responsiveness and effect of preservative.

Inhaled topical lidocaine, used to produce anesthesia of the respiratory tract prior to bronchoscopy, may cause bronchoconstriction in asthmatic patients. We investigated whether the degree of histamine airway responsiveness would predict the development and extent of lidocaine-induced bronchoconstriction in 20 asthmatic patients. The provocation concentration of histamine producing a 20 percent fall in FEV1 (PC20) was measured. On a separate day, challenge with 6 ml 4 percent lidocaine (Xylocaine 4 percent topical) was performed. There was no correlation between the response to lidocaine and the histamine PC20. Five patients (25 percent) showed a fall in FEV1 of greater than 15 percent (max 42.1 percent). Three responders were rechallenged double-blind with the commercial 4 percent lidocaine preparation and with a 4 percent preservative-free lidocaine solution. There was no difference in the response to these two solutions. These results demonstrate that inhaled topical lidocaine induces bronchoconstriction in a significant proportion of patients with asthma. This response is not related to airway histamine responsiveness or to the preservative in the lidocaine preparation.