| Sexually stimulated men with erectile dysfunction do not produce enough no in the penile nerves therefore cgmp levels do not become high enough to relax vascular muscles. So vessels do not dilate blood does not flow into the erectile tissues and the men cannot get erections. When viagra is introduced the low levels of no produced during sexual stimulation are enough because viagra plugs the drain i.e. Pde 5 and allows cgmp to build up and cause an erection. Normal men would not notice much difference in the earlier trials they had reported erections as a result of stimulation but with less stimulation than normal. Unlike injectable therapies viagra has no effect at all in the absence of sexual stimulation. Cgmp is not produced until no appears and no only buy viagra on the scene after sexual stimulation. This was good news because it would make the drug appealing to patients they would not have erections when they did not want them. But it presented a challenge to the design of the clinical trials. How do you test buy viagra drug that requires sexual stimulation to be effective? There was no point in analyzing the effect unless there was sexual stimulation and the quality of the sexual stimulation was going to be important so obviously any assessment in a laboratory was bound to be artificial. The real test had to be in the home setting said osterloh who began designing the first series of trials in 1994. How do you assess that? Anything. |
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