Sexual stimulation causes the release of neurotransmitters from cavernosal nerve endings and relaxation factors from endothelial cells lining the sinusoids. NOS produces NO from L-arginine, and this, in turn, produces other muscle-relaxing chemicals, such as cGMP and cyclic adenosine monophosphate (cAMP), which work via calcium channel and protein kinase mechanisms (see the image below). This results in the relaxation of smooth muscle in the arteries and arterioles that supply the erectile tissue, producing a dramatic increase in penile blood flow.
"For men who are unwilling or unable to self-inject alprostadil, the FDA has approved this dissolvable pellet that can be inserted directly into the urethra, the opening of the penis," says Dr. Feloney. MUSE, with an inspiring name that actually stands for medicated urethral system for erection, will trigger an erection in about 10 minutes that may last as long as an hour. Using MUSE to treat ED can result in somewhat unpleasant side effects, however — including an aching sensation, burning, redness, and minor bleeding.
In a prospective study from the Prostate Cancer Prevention Trial database, Thompson et al reported that men presenting with ED had a significantly higher chance of developing a cardiovascular event over a 7-year follow-up period.  The hazard ratio was 1.45, which is in the range of risk associated with current smoking or a family history of MI.
When it comes to boosting sexual performance, many men will walk all over God’s green earth looking for ways to maintain a good sex life. Luckily men, all you have to do is walk — not run — 2 miles a day. This, along with other healthier lifestyle interventions can help obese men reduce their risk of ED, or even “reverse” current impotence, according to a 2005 study. This comes of importance, since maintaining a trim waistline is a good defense for ED, as men with a 42-inch waist are 50 percent more likely to have ED than those with a 32-inch waist. Getting to a healthy weight and maintaining it is a good strategy for preventing and treating ED.
All of these medicines work by relaxing smooth muscles and increasing blood flow in the penis during sexual stimulation. You should not take any of these medicines to treat ED if you are taking nitrates to treat a heart condition. Nitrates widen and relax your blood vessels. The combination can lead to a sudden drop in blood pressure, which may cause you to become faint or dizzy, or fall, leading to possible injuries.
Alprostadil is injected into the side of penis with a very fine needle. It's of great value to have the first shot in the doctor's office before doing this on your own. Self-injection lessons should be given in your doctor's office by an experienced professional. The success rate for getting an erection firm enough to have sex is as high as 85% with this treatment. Many men who do not respond to oral PDE5 inhibitors can be ‘rescued' with ICI.