This invention provides a dry powder inhaler comprising: a dry powder medicament comprising fluticasone propionate, salmeterol xinafoate and a lactose carrier； wherein, the delivered dose of salmeterol per actuation is less than 50 μg； and wherein the dose provides a baseline-adjusted FEV1 in a patient of more than 150 mL within 30 minutes of receiving the dose. A method of treating a patient includes administering to a patient a dry powder medicament having fluticasone propionate, salmeterol xinafoate and a lactose carrier； wherein, the delivered dose of salmeterol per actuation is less than 50 μg； and wherein the dose provides a baseline-adjusted FEV1 in a patient of more than 150 mL within 30 minutes of receiving the dose.
