Provided herein is a system that includes a metered dose inhaler device for pulmonary delivering to a subject at least one pre-determined vaporized amount of at least one pharmacologically active agent being in a plant material, wherein vaporization is effected by controllably heating the plant material so as to vaporize a pre-determined vaporized amount of the agent; the system further includes a controller in communication with the inhaler device, configured to control the pre-determined vaporized amount based on data indicative of at least one pharmacodynamic effect induced by the agent in the subject.