An inhalation system for delivering a dry powder medicament to a pulmonary tract, comprises a dry powder inhaler configured to have at least two inlet apertures, wherein a first inlet aperture is in communication with a first air flow pathway and a second inlet aperture is in communication with a second air flow pathway. The first airflow pathway and the second airflow pathway converge in a substantially perpendicular manner during an inhalation maneuver for deagglomerating powder particles. The inhalation system has a total resistance to flow in a dosing configuration ranging in value from 0.065 to about 0.200 (√kPa)/liter per minute. The inhaler may contain a cohesive powder e.g. a diketopiperazine, and the powder may contain insulin or another medicament.
