A modular transdermal drug delivery system is provided, the system including: an upper module in which an outer backing layer is laminated to a pressure-sensitive adhesive layer that is covered by a removable release liner prior to assembly； and a lower module with a porous drug reservoir layer laminated to a skin-contact adhesive that affixes the system to the skin during drug delivery, where the skin-contact adhesive is, in one embodiment, an adhesive layer that is substantially co-extensive with the porous drug reservoir layer and, prior to use, protected with a second removable release liner. Methods of manufacture and use are also provided, as is an assembled transdermal drug delivery system fabricated by affixing the pressure-sensitive adhesive layer of the upper module to the porous drug reservoir layer of the lower module.
