A portable medical apparatus for administering a fluid drug in doses, including a first housing including a reservoir unit with an outlet into a fluid path for conducting the drug, a second housing including a conveying unit for dispensing the drug from the reservoir unit in doses and a suitable controller for controlling the conveying unit, an adaptor including a coupling structure for receiving the first housing and the second housing and an attaching structure for extra-corporeally carrying the adaptor on a patient, wherein the conveying unit and the reservoir unit can be joined together to form an integrated mechanical and fluidic unit, and coupled to and decoupled from at least two differently configured adaptors, wherein at least one of the adaptors is configured to be directly attached to the surface of the skin and at least one of the adaptors is configured to be worn on or carried by an article of clothing or a wearing system (e.g., a belt).
