We examined the effect of pyridostigmine (PY) at a dose of 30 mg orall
y three times a day on nonspecific bronchial hyperreactivity in ten no
rmal nonsmokers (NNS), ten smokers (SM), and ten mild asthmatics (AS).
We conducted a double-blind, placebo-controlled, crossover trial, ran
domly assigning subjects to receive either placebo (PL) or PY before u
ndergoing bronchoprovocation challenge with eucapnic voluntary hyperve
ntilation (EVH) using dry gas. Compliance with PY was confirmed by mea
suring red blood cell acetylcholinesterase (Achase) levels during both
days of testing. While taking PL, the mean (+/- SEM) falls in FVC and
FEV, after the bronchoprovocation were as follows: NNS, 1.0 percent (
+/- 0.6) FVC and 4.3 percent +/- 1.0) FEV1; SM, 2.4 percent (+/- 1.1)
FVC and 2.7 percent +/- 1.3) FEV1; AS, 5.3 percent (+/- 2.3) FVC and 1
1.5 percent +/- 2.8) FEV1. The mean decreases in FVC and FEV1 while ta
king PY were as follows: NNS, 1.8 percent (+/- 0.7) FVC and 4.3 percen
t (+/- 0.8) FEV1; SM, 3.8 percent (+/- 1.4) FVC and 5.2 percent (+/- 1
.6) FEV1; AS, 4.4 percent (+/- 1.3) FVC and 11.8 percent (+/- 2.8) FEV
1. Within each category, using a paired t test to compare the results
on each day of testing, no statistically significant differences were
noted. Pyridostigmine at the tested dose has no significant effect on
nonspecific bronchial hyperreactivity in normal NNS, SM, or AS.