A drug delivery system incorporated into a cardiac device for delivering a dose of a drug to a patient upon detection of a particular medical condition. The cardiac device may be, for example, an implantable cardioverter/defibrillator, cardiac pacemaker, or combination device that communicates via a radio frequency link with a drug delivery device. The drug delivery device is preferably an electrically modulated transdermal drug delivery device for delivering the drug transdermally in accordance with a signal received from the cardiac device.