Iontophoretic drug delivery system with two-stage delivery profile.

A two-stage iontophoretic drug delivery system provides that iontophoretic current is delivered at a first level for a first predetermined interval to rapidly introduce a therapeutic agent into the bloodstream and thereafter reduced to a second lower level to maintain a desired steady-state therapeutic level of the agent. One embodiment provides that the initial interval is maintained sufficiently long to provide a peak dosage, thereafter which the current is shut off to allow concentration of the agent to subside in the bloodstream, whereupon a maintenance level of iontophoretic current is initiated. Another embodiment provides that the patient may selectively initiate a brief interval of increased iontophoretic current level to attain a brief interval of increased dosage.