Dr. Benjamin Breyer Urology
San Francisco, CA 94143
Phone: (415) 353-2200

Benjamin Breyer


Urology Practice

400 Parnassus Ave.,
Sixth Floor, Suite A610
San Francisco, CA 94143
Phone: (415) 353-2200
Fax: (415) 353-2641

Hours: Monday to Friday
8 a.m. – 5 p.m.

Request an Appointment

Erectile Dysfunction

Erectile dysfunction (ED) is the most common type of male sexual dysfunction. Erectile dysfunction symptoms can occur at any age. Therefore, both old and young men can need the treatment of this sexual disorder.

The main symptom of erectile dysfunction is inability to achieve and (or) maintain erection of the penis sufficient for sexual intercourse.

  • When symptoms of ED are rare, non-drug methods of preventing erectile dysfunction can be recommended.
  • When ED symptoms are observed for a few weeks or months, drug therapy of sexual dysfunction can be prescribed.

To prevent erectile dysfunction, reduce the risk factors that negatively affect male sexual function. Risk factors of erectile dysfunction can be psychogenic or organic.

  • Psychogenic causes of ED is an emotional stress and discomfort, depression, anxiety, social phobia and other types of psychiatric and neuropsychiatric disorders. A characteristic feature of psychogenic form of erectile dysfunction is nocturnal erections.
  • Organic causes of ED are metabolic disorders (e.g., diabetes), hormonal disorders (low testosterone level), brain or spinal cord injury, cardiovascular diseases, alcohol abuse. In organic form of erectile dysfunction, nocturnal erections are absent and erection problems are gradually progressing.
  • Erectile dysfunction very often develops because of using antihypertensive drugs, antidepressants, synthetic analogues of hormones or steroids. ED caused by the use of drugs is a reversible risk factor, which disappears after the end of a short-term or long-term drug therapy.

Despite a great variety of causes and risk factors, standard methods of treatment are used for the recovery of erectile function.

For quick cure of erectile dysfunction, effective and safe drugs from the group of phosphodiesterase type 5 inhibitors (PDE5 inhibitors) are used today.

This pharmacological group includes about a dozen different drugs, three of which are successfully used to treat erectile dysfunction for many years.

The list of PDE5 inhibitors approved for ED treatment in the developed countries includes the following drugs:

  • Sildenafil
  • Tadalafil
  • Vardenafil

These erectile dysfunction drugs have the same mechanism of action, so their therapeutic properties are identical.

PDE5 inhibitors have the ability to enhance the production of nitric oxide in the penile erectile tissue. Thereby, PDE5 inhibitors increase blood flow to the penis and stimulate the recovery of erectile function.

Despite the fact that Tadalafil, Vardenafil and Sildenafil provide the same effects, each of PDE5 inhibitors for ED treatment has distinctive features.

Information about the benefits of different drugs from the group of PDE5 inhibitors can be found in this comparative review.

  • PDE5 inhibitor – Sildenafil

Sildenafil is one of the most popular erectile dysfunction drugs available at the global pharmaceutical market. Men with ED know this drug under the brand name Viagra.

Sildenafil advantage over other ED drugs is very low price. Sildenafil is manufactured by more than 150 pharmaceutical companies around world.

Therefore, serious competition between hundreds of global manufacturers and regional suppliers affects Sildenafil price.

Sildenafil works as other PDE5 inhibitors, however the duration of its effect is no more than 8 hours.

Some PDE5 inhibitors work much longer than Sildenafil. Therefore, buyers of Sildenafil most often become men who are looking for the cheapest drugs to treat erectile dysfunction.

  • PDE5 inhibitor – Tadalafil

Tadalafil is ED drug, which is the main competitor of Sildenafil. Potential buyers of ED drugs know Tadalafil under the brand name Cialis. Tadalafil advantage over other PDE5 inhibitors is that it works for 36 hours.

Properly chosen dose of Tadalafil helps a man to keep the ability to achieve and maintain erection for a very long period.

Due to the prolonged therapeutic effect, Tadalafil allows to forget about erection problems for long, be sexual active at any time of the day or night, and thereby maintain psychological well-being and harmonious relationships with sexual partner.

Despite a relatively high price of Tadalafil, it is the best-selling erectile dysfunction drug with more than $ 2.3 billion of annual retail sales.

  • PDE5 inhibitor – Vardenafil

Effects of Vardenafil ED drug are very similar to the effects of Sildenafil. Therefore, Vardenafil developers suggested that this drug would be able to become a real competitor to Sildenafil drug.

Twelve years after the onset of retail sales of Vardenafil, the fact that this ED drug lost out to Sildenafil became obvious. One reason for low popularity of Vardenafil is ineffective marketing strategy.

Initially, Vardenafil was positioned as a safe drug for ED treatment in elderly. Elderly men with erectile dysfunction know Vardenafil under the brand name Levitra.

Vardenafil causes side effects less frequently than Sildenafil. However, post-marketing observations show that the efficacy and safety of Vardenafil (Levitra) and Sildenafil (Viagra) - are identical.

Thus, statements that Vardenafil is safer than other PDE5 inhibitors are myth. Thus, the only factor that helps Vardenafil manufacturers to promote this drug at the international market is a relatively low price.


Sildenafil, Vardenafil and Tadalafil are the most popular, but not the only PDE5 inhibitors successfully used to treat erectile dysfunction. In the USA and Europe, a new PDE5 inhibitor - Avanafil, which went on sale under the trademarks Stendra and Spedra, was approved in 2012-2013.

There is very little information on post-marketing studies and reviews about Avanafil. Therefore, the majority of men are wary of the new ED drug preferring to use well known Tadalafil, Vardenafil and Sildenafil drugs for the treatment of erectile dysfunction.

© Dr. Benjamin Breyer