COMBINED INTRAVENOUS LIDOCAINE AND INHALED SALBUTAMOL PROTECT AGAINSTBRONCHIAL HYPERREACTIVITY MORE EFFECTIVELY THAN LIDOCAINE OR SALBUTAMOL ALONE

Background: Airway instrumentation in persons with asthma is linked to the risk of life-threatening bronchospasm. To attenuate the response to airway irritation, intravenous lidocaine is recommended (based on a nimal experiments) and mitigates the response to histamine inhalation in asthmatic volunteers. However, the effects of lidocaine have not be en compared with standard prophylaxis with beta-sympathomimetic aeroso ls. Therefore, the effect of lidocaine, salbutamol, combined treatment , and placebo control were tested in awake volunteers with bronchial h yperreactivity. Methods: After approval from the local ethics committe e, 15 persons, who were selected because they showed a decrease in for ced expiratory volume in 1 s (FEV1) more than 20% of baseline in respo nse to inhaled histamine in a concentration less than 18 mg/ml (PC20), were enrolled in a placebo-controlled, double-blind, and randomized s tudy. The challenge was repeated on four different days and the volunt eers were pretreated with either intravenous lidocaine, inhalation of salbutamol, inhalation of salbutamol plus intravenous lidocaine, or pl acebo. Lidocaine plasma concentrations were also measured. Statistical analyses included the Friedman test and Wilcoxon's rank sum. Results The baseline PC20 was 6.4 +/- 4.3 mg/mL intravenous lidocaine and salb utamol aerosol both significantly increased the histamine threshold to 14.2 +/- 9.5 mg/ml and 16.8 +/- 10.9 mg/ml respectively(mean +/- SD). However,the combination of lidocaine and salbutamol significantly inc reased the PC20, even further to 30.7 +/- 15.7 mg/ml than did salbutam ol or lidocaine alone. Conclusions In volunteers with bronchial hyperr eactivity, both lidocaine and salbutamol attenuate the response to an inhalational histamine challenge, and their combined administration ha s much greater effects than does either drug alone. Accordingly, pretr eatment of patients with bronchial hyperreactivity with both beta-mime tic aerosol and intravenous lidocaine is recommended before airway irr itation.