As you know, the first drug that fundamentally changed ideas about the methods of treatment of erectile dysfunction, was Viagra. Injections into the cavernous tissue of the penis, vacuum pumps, and other invasive procedures have gone to the dustbin of history, giving way to an extremely unpretentious and highly effective drug. The official approval of Viagra by the US Food and Drug Administration (FDA) in 1998 meant that Pfizer received a monopoly on the production of an effective and safe drug, which in the first year of sales brought it more than a billion (!) Dollars . A similar financial idyll for Pfizer lasted 5 years, until the moment when in 2003 two new drugs to increase potency entered the pharmaceutical market - Cialis (tadalafil) and Levitra (vardenafil).
In the history of the drug Cialis there was a place for curiosities. Just like in the case of Viagra, it all started with research. In 1993, the American international pharmaceutical corporation "Aykos" began a full-scale study of the substances of the group of inhibitors of the phosphodiesterase type 5 enzyme (PDE5), namely IC351. To date, drugs based on PDE5 inhibitors are the most promising drugs for the treatment and prevention of erectile dysfunction. But at the end of the last century, the situation was fundamentally different: it will suffice to say that the creation of the first drug of the PDE5 inhibitor group was a happy, but still an accident (see Viagra).