Cough threshold for capsaicin increases by azelastine in patients with cough-variant asthma.
To assess the effects of azelastine in patients with cough-variant asthma, we measured the cough threshold for capsaicin (the concentration required to elicit more than five coughs) in 16 patients with cough-variant asthma before and after 4 weeks of treatment with azelastine (2 mg; b.i.d.) or placebo. After treatment, coughing decreased in all patients and the cough threshold for capsaicin increased significantly, from 0.67 +/- 0.30 microM to 4.76 +/- 1.55 microM (P < 0.01) in the azelastine group. However, the cough threshold for capsaicin did not increase significantly, from 0.86 +/- 0.33 microM to 1.11 +/- 0.35 microM (P > 0.10) in the placebo group. These results suggest that azelastine inhibits coughing in patients with cough-variant asthma.
Shioya
T
T
Second Department of Internal Medicine, Akita University School of Medicine, Japan.
Ito
N
N
Sasaki
M
M
Kagaya
M
M
Sano
M
M
Shindo
T
T
Kashima
M
M
Miura
M
M
D000328:Adult; D000368:Aged; D001249:Asthma / Q000150:complications*; D001993:Bronchodilator Agents / Q000494:pharmacology*; D002211:Capsaicin / Q000009:adverse effects*; D003371:Cough / Q000139:chemically induced* / Q000517:prevention & control; D004305:Dose-Response Relationship, Drug; D005260:Female; D006634:Histamine H1 Antagonists / Q000494:pharmacology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010793:Phthalazines / Q000627:therapeutic use*
D001993:Bronchodilator Agents; D006634:Histamine H1 Antagonists; D010793:Phthalazines; D002211:Capsaicin; C020976:azelastine