A inhaler for an inhalation formulation, comprising a canister containing a pharmaceutical composition under pressure； a metering valve for measuring a metered dose of the composition from the canister for administration to a patient in need thereof； and an actuator for actuating discharge of the metered dose to the patient； wherein the actuator includes a discharge orifice having a diameter in the range 0.2 to 0.4 mm； and wherein the pharmaceutical composition comprises an anticholinergic agent and a pharmaceutically acceptable propellant.
