An erection is a "neurovascular event" meaning that in order to have an erection there needs to be proper function of nerves, arteries, and veins. An erection involves the central nervous system, the peripheral nervous system, physiologic and psychological factors, local factors with the erection bodies or the penis itself, as well as hormonal and vascular (blood flow or circulation) components. The penile portion of the process leading to an erection represents only a single component of a very complex process.
Sildenafil (Viagra) was the first oral phosphodiesterase type 5 (PDE5) inhibitor approved by the FDA in the United States for the treatment of erectile dysfunction (it is not approved for women). Sildenafil inhibits PDE5, which is an enzyme that destroys cGMP. By inhibiting the destruction of cGMP by PDE5, sildenafil allows cGMP to accumulate. The cGMP in turn prolongs relaxation of the smooth muscle of the corpora cavernosa. Relaxation of the corpora cavernosa smooth muscle allows blood to flow into the penis resulting in increased engorgement of the penis. In short, sildenafil increases blood flow into the penis and decreases blood flow out of the penis.
Other treatment options such as penile self-injection therapy, external vacuum pumps and the medicated urethral system for erection are on rare occasions an effective long-term treatment. A very small percentage of men will continue with these treatments as evidenced by a very high drop out rate and a very low refill rate for these treatments. These procedures require extensive planning which interfere with sexual spontaneity and are really not a realistic long-term treatment for young patients with permanent ED.
Erectile dysfunction, also known as ED or impotence, is the inability to attain or maintain an erection of the penis adequate for the sexual satisfaction of both partners. It can be devastating to the self-esteem of a man and of his partner. As many as 30 million American men are afflicted on a continuing basis, and transient episodes affect nearly all adult males. But nearly all men who seek treatment find some measure of relief.
Sildenafil is available as oral tablets at doses of 25 mg, 50 mg, and 100 mg. Patients should take sildenafil approximately one hour before sexual activity. In some men, the onset of action of the drug may be as early as 11-20 minutes. It's best for men to take sildenafil on an empty stomach for best results since absorption and effectiveness of sildenafil can be diminished if it is taken shortly after a meal, particularly a meal that is high in fat. Sildenafil and the other PDE5 inhibitors don't cause an immediate erection. Sexual stimulation is necessary for these medications to work.
Dr. Niket Sonpal is the Associate Program Director of the Internal Medicine Residency at Brookdale Hospital Medical Center in Brooklyn and an Associate Professor at Touro College of Osteopathic Medicine. He's a practicing Gastroenterologist and Hepatologist with a focus on Men's and Women's Health, and a regular contributor to Women's health, Shape and Prevention Magazine.
Wing, R. R., Rosen, R. C., Fava, J. L., Bahnson, J., Brancati, F., Gendrano, I. N. C., … Wadden, T. A. (2010, January). Effects of weight loss intervention on erectile function in older men with type 2 diabetes in the Look AHEAD trial. The Journal of Sexual Medicine, 7(1), 156-165. Retrieved from https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4461030/
The number of sexual dysfunction complaints was significantly associated with the amount of alcohol consumed per day. On curve-fitting the data, there was a significant positive linear relationship (F = 10.54; dF 87; P = 0.002) [Figure 1]. However, there was no correlation between the reduction in frequency of sexual intercourse over the last five years and the amount of alcohol consumed.
Men with diabetes tend to develop erectile dysfunction 10 to 15 years earlier than men without diabetes. As men with diabetes age, erectile dysfunction becomes even more common. Above the age of 50, the likelihood of having difficulty with an erection occurs in approximately 50% to 60% of men with diabetes. Above age 70, there is about a 95% likelihood of having some difficulty with erectile dysfunction.