Inhaler

An inhaler comprising a housing, a blister strip contained within said housing, said blister strip having a surface and a plurality of blister pockets depending from said surface, each blister pocket containing a dose of medicament for inhalation by a user and, a blister strip drive mechanism including a drive wheel comprising a plurality of spokes, each spoke forming an arm of the blister drive mechanism, and a blister strip drive member shaped to contact the strip along a line defined by a crease between a blister pocket and said surface, to drive said strip, the blister strip drive member having leading and trailing blister strip contact edges on opposite sides of an axis extending in a radial direction through said arm and the blister strip drive member so that the leading blister strip contact edge contacts the strip along a line defined by the crease between one blister pocket and said surface when the drive member is rotated in one direction and so that the trailing blister strip contact edge contacts the strip along a line defined by the crease between an adjacent blister pocket and said surface, when the drive member is rotated in the opposite direction, wherein a blister separation, which is the distance between the creases of adjacent blister pockets, is substantially the same as the distance between the leading and trailing edges of the blister strip drive member and wherein the pitch of the blister strip is selected so that it is less than the pitch of the drive wheel, with the pitch of the blister strip being equal to the width of the blister plus the blister separation and the pitch of the blister strip drive member being equal to the length of a chord of the blister strip drive member plus the width of a tip of the blister strip drive member.