A dry powder inhaler (10) having a chamber (26) divided into first and second blister compartments (28, 30) for storing unused and used portions (34, 36) of a blister strip (12) is provided. A moveable dividing wall (32) separates the first and second blister compartments. One or more arcuate supporting surfaces (38, 40, 42) are disposed in either the first and/or the second blister compartments and these surfaces support the used or unused blister strip during successive actuations of the inhaler. Use of the arcuate supporting surfaces facilities compact coils of unused and used portions of blister strip, thereby reducing the size of the chamber required for the inhaler.