A stimulating medical device comprising a stimulating assembly implantable proximate to nerve cells of a recipient having at least one agent delivery port and a plurality of electrical contacts; an electrical stimulation controller configured to generate electrical stimulation signals for application to a first population of the nerve cells via one or more of the plurality of electrical contacts; a pharmaceutical agent source configured to provide a pharmaceutical agent to the at least one delivery port for application to a second population of the nerve cells; and a pharmaceutical agent controller configured to control one or more of the pharmaceutical agent source and the at least one delivery port to cause selective application of the pharmaceutical agent to the second population of nerve cells.