Treatment with SB-@ produced a significant improvement in cough reflex sensitivity to capsaicin at @ hours and a borderline significant improvement at @ hours compared with placebo ( adjusted mean difference of +@ doubling doses at @ hours -LSB- @ % CI , +@ to +@ ; P = @ -RSB- and +@ doubling doses at @ hours -LSB- @ % CI , +@ to +@ ; P = @ -RSB- ) .