The present invention comprises a transdermal dosage form comprising an active agent component having a skin contacting surface, an adverse agent component, and a barrier. The dosage form comprises at least one channel passing between proximal and distal surfaces of the active agent component. The barrier is interposed between the active agent component and the adverse agent component. In one aspect, the barrier is permeable to selected solvents and impermeable to diffusion of active and adverse agents in the absence of said solvent. In another aspect, the barrier is discontinuous, impermeable to diffusion of active and adverse agents, and the dosage form comprises at least one channel passing between the skin-contacting surface and the adverse agent component.