Phosphodiesterase 3 inhibition and cough in elderly asthmatics.
OBJECTIVE
Cough is a common symptom of bronchial asthma, a chronic inflammatory airway disease. Recently, the therapeutic effects of selective phosphodiesterase (PDE) inhibitors have been focused on bronchial asthma. This study was designed to investigate the clinical effect of PDE 3 inhibition on cough reflex sensitivity in elderly patients with bronchial asthma.


METHODS
Effects of cilostazol, a PDE 3 inhibitor, on cough response to inhaled capsaicin were examined in 11 patients over 70 years with stable asthma in a randomized, placebo-controlled cross over study. Capsaicin cough threshold, defined as the lowest concentration of capsaicin eliciting five or more coughs, was measured as an index of airway cough reflex sensitivity.


RESULTS
The cough threshold was significantly (p < 0.05) increased after two-week treatment with cilostazol (100 mg twice a day orally) compared with placebo [48.8 (GSEM 1.4) vs. 29.2 (GSEM 1.3) muM].


CONCLUSIONS
These findings indicate that PDE 3 inhibition may be a novel therapeutic option for elderly patients with asthma, especially for their cough symptoms.
Ishiura
Yoshihisa
Y
The Department of Internal Medicine, Toyama City Hospital, Toyama, Japan. ishiura@tch.toyama.toyama.jp.
Fujimura
Masaki
M
Nobata
Kouichi
K
Abo
Miki
M
Oribe
Takayoshi
T
Myou
Shigeharu
S
Nakamura
Hiroyuki
H