Am. J. Respir. Crit. Care Med., Vol 151, No. 1, Jan 1995, 222-225.
Bronchodilator and bronchoprotective effects of cilostazol in humans in vivo
M Fujimura, Y Kamio, M Saito, T Hashimoto and T Matsuda
Third Department of Internal Medicine, Kanazawa University School of Medicine, Kanazawa University Hospital, Japan.
Cilostazol is a selective orally active phosphodiesterase (PDE) III
inhibitor. This study was conducted to evaluate whether inhibition of PDE
subtype III can reduce bronchial responsiveness. We examined the effects of
cilostazol on bronchial responsiveness to methacholine in eight normal
subjects by a single-blinded, crossover study. Each subject received 200 mg
of cilostazol or placebo in random order. The subjects underwent
methacholine challenge test 3 h after administration of each drug on two
occasions separated by 5 d or more. The geometric mean value of provocative
concentration of methacholine causing a 20% fall in FEV1 (PC20-FEV1) and
the mean value (+/- SEM) of maximum expiratory flow on partial flow-volume
curve at isovolume of 40% FVC above residual volume (PEF40) after
administration of cilostazol were 25.3 (geometric standard error of the
mean [GSEM], 1.35) mg/ml and 3.78 +/- 0.31 L/s, which were significantly (p
< 0.02 and p < 0.05) greater than those after the placebo
administration (6.81 [GSEM, 1.42] mg/ml and 2.71 +/- 0.39 L/s). All
subjects complained of mild to severe headache when cilostazol was given.
These findings suggest that PDE III inhibitors such as cilostazol have
bronchodilator and bronchoprotective effects in humans. Further studies
regarding smaller oral dosing of or aerosol administration of cilostazol or
the other PDE III inhibitors are needed to determine clinical usefulness.
