The invention generally relates to internal (e.g., implantable, insertable, etc.) drug delivery devices which contain the following: (a) one or more sources of one or more therapeutic agents; (b) one or more first electrodes, (c) one or more second electrodes and (d) one or more power sources for applying voltages across the first and second electrodes. The power sources may be adapted, for example, to promote electrically assisted therapeutic agent delivery within a subject, including electroporation and/or iontophoresis. In one aspect of the invention, the first and second electrodes are adapted to have tissue of a subject positioned between them upon deployment of the medical device within the subject, such that an electric field may be generated, which is directed into the tissue. Furthermore, the therapeutic agent sources are adapted to introduce the therapeutic agents into the electric field. In another aspect, the therapeutic agent sources are polymeric regions that contain one or more types of ion-conductive polymers and one or more types of charged therapeutic agents. In yet another aspect, the therapeutic agent sources are polymeric regions that contain one or more types of electrically conductive polymers and one or more types of charged therapeutic agents.