Am. J. Respir. Crit. Care Med., Vol 154, No. 4, 10 1996, 885-888.
Intravenous lidocaine and oral mexiletine block reflex bronchoconstriction in asthmatic subjects
H Groeben, WM Foster and RH Brown
Department of Anesthesiology and Environmental Health Services, The Johns Hopkins Medical Institutions, Baltimore, Maryland, USA.
Stimulation of the airways of asthmatic individuals causes severe
bronchoconstriction, which is in part neurally mediated via the vagus
nerve. Local anesthetics are commonly administered to prevent this
reflex-induced bronchoconstriction. Therefore, in a double-blind,
placebo-controlled prospective study, we tested the effectiveness of oral
mexiletine and intravenous lidocaine at blocking histamine-induced reflex
bronchoconstriction. Fifteen subjects with mild asthma were selected (for
whom the provocative concentration of histamine aerosol causing a 20%
decrease in FEV1 (PC20) was less than 18 mg/ml). Subsequently, the subjects
were pretreated with oral mexiletine, intravenous lidocaine, or placebo,
and the histamine challenges were repeated. The baseline PC20 for histamine
was 8.8 +/- 1.8 mg/ml. Mexiletine and lidocaine at therapeutic serum
concentrations blocked reflex bronchoconstriction. Oral mexiletine
increased the PC20 to 21.1 +/- 5.0 mg/ml (serum concentration: 0.7 +/- 0.05
microg/ml). Likewise, intravenous lidocaine increased the PC20 to 24.5 +/-
4.9 mg/ml (serum concentration: 2.6 +/- 0.15 microg/ml). Oral mexiletine
and intravenous lidocaine block reflex-induced bronchoconstriction.
Furthermore, mexiletine may have additional airway benefits when selected
for the treatment of dysrhythmias or chronic pain in patients with
coexisting lung diseases.
