An implantable medical device is capable of delivering therapeutic output to a patient. A controller, programmable by a medical professional, is operatively coupled to the implantable medical device to, in part, program the therapeutic output to be delivered to the patient. The controller has an interface allowing the medical professional to graphically select an amount of the therapeutic output to be delivered to the patient in at least one of a series of discrete timer intervals. The graphic selection may be aided by the use of a light pen or other pointing device to sketch the infusion pattern. Computer programs using algorithms may be utilized to translate the information inputted through the light pen into an infusion program.