Various embodiments relate to a device for dispensing a plurality of unitary doses of dry powder. The device includes: a casing; first and second supports respectively for two carriers each having a plurality of housings for respective unitary doses adapted to be connected to the mouthpiece for inhalation of the dose, the first and second supports being moveably mounted within the casing for sequentially connecting the housings to the mouthpiece; an indexing mechanism adapted to engage and move the first and second supports; and a changeover mechanism adapted to cause the device to pass from a first dispensing state to a second dispensing state and lock the second support in its stationary position while the device is in the first dispensing state, and to lock the first support in its stationary position while the device is in the second dispensing state.