Objective
To study the erectile response to intracavernosal injection of prostaglandin E1 in 33 spinal cord injured men with neurogenic erectile dysfunction.

Method
The erectile response was assessed by the penile palpation. Thirty three subjects (mean age, 35.5 years) were studied. They received a testing dosage starting from 2.5 μg with increasing dosage (maximum 40 μg) to achieve an erection. The positive response accounts for the sufficient erection lasting for more than 30 minutes.

Results
After the injection, 30 subjects (90.9%) achieved the positive response and the mean duration of erection was 59.2 minutes. Of the 30 positive responders, the mean dosage needed to induce positive response was 5.8 μg in the patients with cervical cord injury (12 subjects), 13.1 μg in the patients with thoracic cord injury (12 subjects), and 33.3 μg in the patients with lumbar cord injury (6 subjects). The mean dosage required for the positive response was different according to the pre-injection erectile function of the subjects. For the positive response, it required 7.7 μg in a full erection with short duration group (14 subjects), 9.4 μg in a partial erection group (8 subjects), and 30.6 μg in no erection group (8 subjects). No systemic side effect or complication was noted except for the prolonged erection in 1 subject.

Conclusion
The intracavernosal injection of prostaglandin E1 appears to be a safe and effective treatment for the treatment of erectile dysfunction in spinal cord injured men. The dosage depends on the level of spinal cord injury and pre-injection erectile function.