Embodiments of the invention provide patch assemblies for iontophoretic transdermal delivery of therapeutic agents. An embodiment provides a patch assembly comprising a conformable patch for delivery of the agent and having a tissue contacting side including an adhesive. The housing has a bottom surface for engaging a non-tissue contacting side of the patch, a current source such as a battery and a controller for controlling the delivery of the agent. The housing has sufficient flexibility such that when it is engaged with the patch to form the patch assembly and the patch is adhered to a target site on the patient's skin, the assembly has sufficient flexibility to deform with movement of the patient's skin to remain sufficiently adhered to the skin over an extended period of time to transdermally deliver a desired dose of the agent. Embodiments of the assembly may used to deliver a variety of therapeutic agents.