Erectile Dysfunction and the Development of Cialis to Treat It

Cialis History and Development


Erectile dysfunction, often shortened to simply ED, has been thrust to the forefront of medical news ever since Viagra appeared on the market in 1998. Since that time, Viagra, manufactured by Pfizer Corporation, has been joined by two other big-name medications for the treatment of erectile dysfunction. Levitra, a product of Bayer and GlaxoSmithKline, appeared in 2003. Just after the launch of Levitra, Cialis broke on the market later that same year.

Cialis is the result of a collaboration between the biotechnology company, Icos, and pharmaceutical giant, Eli Lilly.

History of Erectile Dysfunction

The term “erectile dysfunction” refers to one aspect of male sexual dysfunction, specifically the ability to regularly achieve or maintain an erection. Impotence, on the other hand, has historically been a blanket term indicating any element of malfunction in the male sexual activity, including physical or mental stimulation, ejaculation problems, and erectile dysfunction.

Before the recent triad of oral medications, men experiencing erectile dysfunction relied on other treatment options, if they were willing to reveal problems at all. ED, once a taboo topic of discussion, has been estimated to afflict millions of men, some as young as in their forties. Prior to oral treatments, options for erectile dysfunction treatment included penile injections, implants, and vacuum devices that literally draw blood into the penis, thereby allowing an erection. Men with mild arterial obstructions could also possibly be relieved of erectile dysfunction by surgical procedures. And still others, with hormone imbalances, might benefit from testosterone supplements.

Phosphodiesterase Type 5 Inhibitors

This newest generation of medications are known as phosphodiesterase Type 5 inhibitors, or PDE5 inhibitors. They target specifically the problem of consistent blood flow to the penis. Pfizer was first to discover the relationship between phosphodiesterase enzymes and their relationship to normal penile erection. They developed their drug’s agent, sildenafil, and found it would suppress the PDE5 enzyme, thereby allowing a production of cyclic guanosine monophosphate (cGMP) that promotes muscle tissue relaxation in the penis. When the muscle tissue relaxes, normal brain stimulus occurs allowing a regular penile erection. Pfizer’s discoveries opened the door to further research and rapid advances in the field. Lilly/ICOS found that tadalafil, the agent in Cialis, would effectively suppress the PDE5 enzyme much the same as sildenafil does in Viagra. However, Lilly/ICOS believe their product is beneficial in the treatment of ED because it delivers a long-lasting, up to 36 hours, window of action. Not that a man should have an erection for 36 hours, but that the medication remains available to the body so that sexual activity does not have to be rushed.