The invention relates to dry powder pharmaceutical compositions and their administration by means of inhalers in the treatment of chronic obstructive pulmonary disease (COPD), asthma and other obstructive airway diseases.L'invention concerne des compositions pharmaceutiques de poudre sèche et leur administration au moyen d'inhalateurs dans le traitement de la bronchopneumopathie chronique obstructive (BPCO), de l'asthme et d'autres maladies respiratoires obstructives.