Caverject is administered via small-needle injection into an area of the penis known as the corpus cavernosum. It works by relaxing smooth muscle tissue which, in turn, enhances blood flow to the penis, creating an erection. The drug is indicated for the treatment of erectile dysfunction whether the cause is neurological, vascular, psychological or of mixed origin. Patients selected for treatment with Caverject receive initial injections from medically-trained personnel to determine optimum dosing. Caverject can be administered by the patient once he has been trained to self-inject.