Capsaicin evoked cough responses
Rather than reducing cough responses, lesogaberan treatment was
associated with a small, increase in the maximal cough response (Emax
mean 13.4 coughs, 95% CI 10.1-17.9) compared with placebo (11.8 coughs,
95%CI 8.8-15.9; p= 0.04), but had no effect on ED50 (geometric mean
47.4 μM CI 24.4-91.7 vs placebo 37.6 CI 19.2-73.5 p=0.37). In contrast,
baclofen had no significant effect on Emax (11.1, CI8.1-15.4; p=0.23),
but ED50 was significantly increased compared with placebo (geometric
mean 75.2μM 95%CI 37.2-151.8 p=0.002), i.e. approximately 1 doubling
dose higher, indicating that the volunteers tolerated higher doses of
capsaicin without coughing. There was no evidence of any period effect
for either Emax (p=0.39) or ED50 (p=0.41) in these GEE models. There
were too few subjects in this study for sequence effect to be assessed
as in some cases only 2 subjects had the same sequence of treatment
periods.