The Prostate Cancer Prevention Trial was a landmark study by Thompson et al that prospectively assessed the time to developing CVD after the diagnosis of ED. There were 4247 men with no ED at study entry; 2420 developed incident ED (defined as the first report of ED of any grade) over 5 years. Those men that developed ED had a 1.45-fold higher probability of experiencing a CV event compared with men who did not develop ED.27
Vardenafil and tadalafil belong to the same group of chemical compounds as sildenafil, namely phos-phodiesterase type 5 (PDE-5) inhibitors. Some men cannot benefit from sildenafil or the two newer PDE-5 inhibitors because they have low levels of nitric oxide. British investigators reported in late 2002 that three different types of compounds are being studied as possible medications for men with low levels of nitric oxide. They are Rho-kinase inhibitors, soluble guanylate cyclase activators, and nitric oxide-releasing PDE-5 inhibitors.
Diabetes mellitus: Erectile dysfunction tends to develop 10 to 15 years earlier in diabetic men than among nondiabetic men. The increased risk of erectile dysfunction among men with diabetes mellitus may be due to the earlier onset and greater severity of atherosclerosis (hardening of the arteries) that narrows the arteries and thereby reduces the delivery of blood to the penis. Atherosclerosis can affect the arteries in the penis, as well as the arteries in the pelvis that supply the penile arteries. Diabetes mellitus also causes erectile dysfunction by damaging nerves that go to the penis, much like the effect of diabetes on nerves in other areas of the body (diabetic neuropathy). Diabetes can also affect the muscles in the penis, leading to troubles with erections. Smoking cigarettes, obesity, poor control of blood glucose levels, and having diabetes mellitus for a long time further increase the risk of erectile dysfunction in people with diabetes.
It is important to understand that ED is frequently, if not usually, directly related to endothelial dysfunction, and that the release of NO by the vasculature of the penile arteries is directly related to the function of intact, healthy endothelium. In the face of endothelial dysfunction, the process of erection fails to occur in a normal fashion.16
The role of the endothelium in erectile function became clearer with the observation that the phosphodiesterase type 5 (PDE5) inhibitor, sildenafil, enhanced erectile function. Erection occurs with the release of nitric oxide (NO) from the vascular endothelial cells.17 The reduction in endothelial cell production of NO results in the negative impact on the smooth muscles in the corporal bodies and results in less relaxation of the smooth muscle cells with decrease in blood supply and resulting ED. A similar phenomenon is well known to impact the coronary arterial system resulting in CVD.
A physical examination is necessary. The doctor will pay particular attention to the genitals and nervous, vascular, and urinary systems. Your blood pressure will be checked because several studies have demonstrated a connection between high blood pressure and erectile dysfunction. The physical examination will confirm information you gave the doctor in your medical history and may help reveal unsuspected disorders such as diabetes, vascular disease, penile plaques (scar tissue or firm lumps under the skin of the penis), testicular problems, low male hormone production, injury, or disease to the nerves of the penis and various prostate disorders.
For best results, men with ED take these pills about an hour or two before having sex. The drugs require normal nerve function to the penis. PDE5 inhibitors improve on normal erectile responses helping blood flow into the penis. Use these drugs as directed. About 7 out of 10 men do well and have better erections. Response rates are lower for Diabetics and cancer patients.