Background: Over the last few years, evidence has accumulated that cyclic nucleotide phosphodiesterase (PDE) 3 and/or PDE4 inhibitors may be useful for the treatment of asthma. The present study was designed to examine the effect of a selective orally active PDE3 inhibitor, cilostazol, on bronchial hyperresponsiveness (BHR) of asthma.
Methods: The effect of a single oral dose of cilostazol on BHR was studied in 10 elderly patients with clinically stable asthma, with a mean age of 59.5+/-4.8 years, in a double-blind, crossover, placebo-controlled study. Each subject received 100 mg of cilostazol, 200 mg of theophylline as a positive control or a placebo in a random order. The subjects underwent a methacholine challenge test 3 h after each drug administration on three occasions separated by 2 weeks.
Results: The geometric mean value of the provocative concentration of methacholine causing a 20% fall in forced expiratory volume in 1 s (PC20-FEV1) with cilostazol was 0.48 mg/ml [geometric standard error of the mean (GSEM), 1.40] which was significantly (p<0.01) greater than that with the placebo [0.25 mg/ml (GSEM, 1.36)]. The value with theophylline [0.32 mg/ml (GSEM, 1.54)] did not differ significantly from that with cilostazol or the placebo. Baseline forced vital capacity (FVC) and FEV1 values significantly (p<0.05 and p<0.001, respectively) increased with cilostazol from 2.73+/-0.25 and 1.52+/-0.17 to 2.86+/-0.23 and 1.65+/-0.17 liters, respectively. Theophylline did not significantly increase the FVC or FEV1 value.
Conclusion: It is suggested that the PDE3 inhibitor, cilostazol, has bronchodilator and bronchoprotective effects in elderly asthmatics.