Original Research

Effect of add-on therapy of tiotropium in COPD treated with theophylline

Tomotaka Kawayama, Tomoaki Hoshino, Masao Ichiki, Toru Tsuda, Masaharu Kinoshita, et al

International Journal of Chronic Obstructive Pulmonary Disease 2008, 3:137-147

Published Date: 7 March 2008