Τhe term sexual dysfunction provides a broader concept which includes disorders related to the libido (desire for sexual act), erectile function, ejaculation and orgasm. Erectile dysfunction is defined as the prolonged inability to achieve and/or maintain erections necessary for a complete satisfactory sexual intercourse. Although a benign condition, it has a particularly adverse impact on the quality of life for patients, their families and by extension their social and professional environment.

What is the frequency of erectile dysfunctions?
Erectile dysfunctions are a very frequent pathological condition. Until recently, epidemiological data was based only on Kinsley's in 1948, a groundbreaking study for its time but with many methodological problems. Based on the data of that survey, 42% of men exhibited some kind of disorder of the erectile mechanism. In 1994 they published the results of a large epidemiological survey in 1300 men aged 40-70 years (Massachusetts Male Aging Study, MMAS). The percentage of men who reported some degree of disorder of their erectile mechanism reached 52%. 17% had a low degree of disturbances, 25% a moderate degree and 10% had a complete absence of erections.

What are the factors associated with erectile dyfunction?
Age seems to play a key role, as the total absence of erections triples from 40 (5%) to 70 years (15%). But when all the factors associated with increased impairment are taken into account, it has been found that systemic diseases, living habits and psychological factors significantly affect the onset of erectile dysfunction. It has also been found that diabetes, coronary heart disease, hypertension, low HDL cholesterol values, smoking, various medications (antihypertensives, cardiac medications, psychotropic medications, etc), as well as psychological factors, such as anger and depression are the main causes responsible for erectile dysfunction.

What are the mechanisms of erection?
Unfortunately, and despite the fact that early studies of neurophysiology and pharmacology of erection began about a century ago, for many years our knowledge on the subject has been limited. In the last 15 years, the pioneering work of many researchers and clinicians has allowed for a better understanding of both the central and peripheral mechanisms that control erection. Today, it is known that the main neurotransmitter of erection is nitric oxide (NO) and that erectile function results from a combination of the conservation of the ratio between the smooth muscle and connective tissue of the cavernous body of the penis as well as the metabolic balance between contraction and relaxation mechanisms of the penile smooth muscles.

How much progress have we had in treating erection disorders?
The discovery of Sildenafil (Viagra), in 1998, was considered revolutionary because it is an effective drug and also because it has opened the way to a class of substances, inhibitors of phosphodiesterase 5 (PDE5), which are the key elements for the treatment of erectile dysfunction. Today, new pharmaceutical formulations with high efficacy and patient friendly administration are available on the market (Tadalafil, Cialis).

However, as it has been already mentioned, erectile dysfunction is a medical problem with social implications and its consequences are not only limited to the patient suffering from it but they extent to the couple as a whole. Thus, the treatment should be aimed at restoring the disrupted sexual relationship and not only at improving erection.

Long-term experience (since 1982) by utilizing intracavernosal administration of vasoactive substances, showed that it constitutes a reliable solution in the treatment of erectile dysfunction because it is accompanied by a very high response rate and provides a relatively safe and predictable erection. However, because of the difficulty of their administration, such vasoactive substances are not readily accepted by many patients.

Today, 15 years after the discovery of Sildenafil and a few years of utilizing Tadalafil and Cialis, the possibility that different patients may be more responsive to different drugs is being considered.