i believe this is the complete abstract:
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THE JOURNAL OF UROLOGY - Vol. 157, No.4, Supplement, April 14,1997 Abstract #702
SILDENAFIL (VIAGRAT): A DOUBLE-BLIND, PLACEBO-CONTROLLED, SINGLE-DOSE, TWO-WAY CROSSOVER STUDY IN MEN WITH ERECTILE DYSFUNCTION CAUSED BY TRAUMATIC SPINAL CORD INJURY. Fadel Derry, Brian P. Gardner, Stoke-Mandeville, UK; Clive Glass, Matthew Fraser, Southport, UK; Wallace W. Dinsmore, Belfast, UK; Gary Muirhead, Murray C. Maytom, Malcolm Orr, Sandwich, UK (Presentation by G. Muirhead).
INTRODUCTION AND OBJECTIVES: Penile erection is mediated by nitric oxide via cyclic guanosine monophosphate (cGMP). Sildenafil is a selective inhibitor of type 5 phosphodiesterase, the predominant isozyme causing the inactivation of cGMP in the human corpus cavernosum. Through this increase in cGMP, sildenafil produces a pro-erectile effect.
This study was designed to determine the efficacy, safety, and toleration of single oral doses of sildenafil in spinal cord injury (SCI) patients with erectile dysfunction (ED). Additionally, the relationship between plasma concentrations of sildenafil and the erectile response achieved in these patients was investigated.
METHODS: The study had a double-blind, randomised, placebo-controlled, single-dose, two-way crossover design. Patients with ED solely attributable to SCI were screened; only those with at least a grade 2 reflexogenic erectile response to a vibrator were included. Fasted patients were randomised to receive a single oral dose of 50 mg of sildenafil or placebo, administered in double-blind fashion in a private room. A washout period of at least 3
days occurred between the crossover periods. Reflexogenic erections were stimulated by applying a vibrator to the shaft and glans of the penis at: T=0 (pre-dose), and T=0.5 hour, T=1 hour, and T=1.5 hours post-dose. Efficacy was evaluated by RigiScan c recordings. Plasma samples for assessing drug concentrations were collected after the final RigiScanc recording at T=1.5 hours.
RESULTS: Twenty-seven male patients (mean age 32.9 years, range 21-49 years) with ED solely attributable to SCI (cord level range T6 - L4/5) were studied, one patient did not complete the study.
No patients discontinued treatment due to adverse events.
A total of 17 of 26 (67%) patients on sildenafil had penile base rigidity >60% [median duration (range) = 10 minutes (0.5 - 72.5)], whereas only 2 of 26 (8%) patients on placebo had penile base rigidity >60% duration 2 and 4 minutes); this difference was statistically significant (p<0.01).
In general, patients with the highest plasma sildenafil concentrations achieved the greatest erectile response. Of 20 patients with plasma concentrations >100 ng/ml, 16 (80%) exhibited a response of >60% penile base rigidity on RigiScanc, whilst only 1 of 6 (17%) patients with plasma concentrations <100 ng/ml exhibited such a response.
CONCLUSION: The results indicate that sildenafil is a promising oral treatment of ED in SCI patients with reflexogenic erectile capacity. |
