The Response to Lidocaine in Bronchial Asthma

Abstract

The effect of aerosol administration of lidocaine (40 mg and 100 mg doses) was examined in 22 patients with stable asthma. The initial response in all was a fall of approximately 20 percent in expiratory air flow rates within five minutes after administration of the drug. Thereafter, a bimodal response occurred. Group 1 (12 patients) continued to exhibit this reduction, with the following maximal decreases after ten minutes of delivery of the drug: –24.6 percent decrease in the forced vital capacity (FVC); –38.0 percent decrease in the forced expiratory volume in one second (FEV_1.0); and 42.6 percent decrease in the maximal midexpiratory flow rate (MMEFR). Group 2 (ten patients) manifested a significant improvement in airway resistance, with the following maximal increases at approximately 45 minutes after administration: 11.8 percent increase in FVC; 25.2 percent increase in FEY_1.0; and 41.0 percent increase in MMEFR. These changes were greatest with the 100 mg dose of lidocaine. Intravenously administered lidocaine (1 mg/kg of body weight) aborted the initial bronchoconstriction in all patients but was only mildly effective as a bronchodilator. Lidocaine was also capable of protecting against challenge with methacholine chloride. The possible mechanisms of this divergent response are discussed.