The present invention is directed towards instruments and methods for discharging an anesthetic drug on a continuous basis for use as a nerve block. In accordance with the present invention, a catheter assembly is provided that comprises an electrically conductive wire, a protective sheath and an inflatable balloon. The inflatable balloon is at the distal end of the catheter capable of being inflated and deflated. A balloon channel terminates within the inflatable balloon at the distal end of the catheter and extends proximally along the length of the catheter to the proximal end of the catheter. The balloon channel has a balloon channel opening at a distal end of the balloon channel within the inflatable balloon, capable of releasing an injected substance into the inflatable balloon. The balloon channel further has a balloon channel injection opening at a proximal end of the balloon channel, capable of receiving an injected substance.
