An aerosolization apparatus comprises a container containing a pharmaceutical formulation, the pharmaceutical formulation comprising an active agent and a propellant. The aerosolization apparatus further comprises a metering chamber in communication with the container, the metering chamber adapted to hold a metered amount of the pharmaceutical formulation, a valve to allow the metered amount of the pharmaceutical formulation to be released from the metering chamber when the valve is actuated, and a pressurizer that applies pressure to the pharmaceutical formulation in the metering chamber while the pharmaceutical formulation is being released from the metering chamber. In one version, the metering chamber is sized so that at least 2 mg, and preferably at least 5 mg, of the active agent is be aerosolized for delivery to a user during inhalation.