Fa. Derry et al., Efficacy and safety of oral sildenafil (Viagra) in men with erectile dysfunction caused spinal cord injury, NEUROLOGY, 51(6), 1998, pp. 1629-1633
Objective: To evaluate the efficacy and safety of 50-mg doses of sildenafil
during a 28-day period in patients with erectile dysfunction caused by spi
nal cord injury (cord level range, T6 through L5). Background: Sildenafil i
s an orally active, potent, and selective inhibitor of phosphodiesterase ty
pe 5, an important regulator of cyclic guanosine monophosphate in the human
corpus cavernosum. Methods: To be included in this double-blind, placebo-c
ontrolled study, all patients had to be able to achieve at least a partial
reflexogenic erectile response to penile vibratory stimulation. The study u
tilized a single triangular sequential trial design. A total of 27 patients
were randomized to receive 50 mg of sildenafil or placebo, taken orally as
required (not more than once daily) approximately I hour before sexual act
ivity. Results: After 28 days of treatment, nine of 12 patients (75%) on si
ldenafil and one of 14 patients (7%) on placebo reported that treatment had
improved their erections (p = 0.0043). Furthermore, eight of 12 patients (
67%) on sildenafil and two of 13 patients (15%) on placebo indicated that t
hey wished to continue treatment (p = 0.018). A significant improvement in
satisfaction with their sex life was reported by patients taking sildenafil
(p = 0.012). No patients discontinued treatment due to adverse events. Con
clusion: Oral sildenafil, taken as required (not more than once daily), sig
nificantly improves the quality of erections and satisfaction with sex life
in men with erectile dysfunction caused by a spinal cord injury between T6
and L5.