A method for the fail-safe termination of in vivo drug delivery from an implantable drug delivery system, the method comprising: providing an implantable drug delivery system comprising: a housing having a reservoir for containing a drug, and a port for dispensing the drug to a patient and an emergency deactivation unit disposed between the reservoir and the port, the emergency deactivation unit comprising a composite structure comprising a biocompatible ferromagnetic mesh open to fluid flow and a hydrophobic meltable material, the hydrophobic meltable material comprising at least one hole therein for enabling a fluid to pass through the hydrophobic meltable material implanting the implantable drug delivery system within a patient enabling the drug to flow from the reservoir, through the at least one hole in the hydrophobic meltable material and out the port and when drug flow is to be terminated, applying a magnetic field to the composite structure, such that a current is induced in the ferromagnetic mesh which heats the ferromagnetic mesh and melts the hydrophobic meltable material, thereby closing the at least one hole in the hydrophobic meltable material and blocking drug delivery to the patient.