To provide an accurate, uniform and consistent dispersion when used with a multidose dry powder inhaler.

This dry powder inhalation composition includes a mixture of: particles of formoterol or a pharmaceutically acceptable derivative thereof; and lactose particles with a volume-average diameter of about 70 to about 120 μm and a diameter of less than 250 μm, wherein up to 96 wt.% of the lactose particles are less than 150 μm in diameter, and up to 25 wt.% of the lactose particles are less than 5 μm in diameter. Furthermore, a method for using the composition is disclosed.