Category - Part 2
The History of Cialis
Since the March 27th 1998 FDA approval of the prescription drug Viagra, Pfizer, enjoyed a five plus year monopoly of being the only prescription drug company that could distribute the erectile dysfunction drug Sildenafil Citrate. And as such sold over 1 billion dollars worth of the drug in just the first year of introduction. This finally changed on August 19, 2003 with the FDA approval of Levitra and November 21, 2003 FDA approval of Cialis.
The development of the impotence prescription drug Cialis has an interesting beginning (The History of Cialis). The drug company Icos actually began studies on a PDE5 enzyme inhibiter called IC351 in 1993. This is the process by which all erectile dysfunction drugs work. Interestingly enough, in 1994 scientist for Pfizer discovered that Sildenafil Citrate caused heart patients to get an erection during clinical studies of the heart medicine.
One can only assume that testing that was being conducted for the chemical compound IC351 was not being tested for erectile dysfunction. Little did they know that the compound that was similar in effect to Sildenafil Citrate, just one year later would be discovered as a potential impotence medication by another drug company, Pfizer.
The Bothell, Washington-based company, Icos, that began operations in 1990, received its first patent on IC351 in 1994. It is uncertain whether whether the patent was granted before or after the Pfizer discovery. Phase I clinical trials began in 1995. And after two years of testing, phase II clinical studies began. During this phase, 1997 marked the year that Icos conducted its first study in patients with erectile dysfunction. This phase lasted for two year up to the final third phase.
In 1998, Icos and Eli Lilly and Co. joined forces to commercialize the drug for the treatment of sexual dysfunction. Two years later the new company filed a new drug application with the U.S. Food and Drug Administration for IC351 and renamed the drug Cialis.
On May 2002 Lilly and Icos reported to the American Urological Association that Phase III test results for Cialis concluded that Cialis remained in the system and kept working for up to 36 hours. These findings were presented at the 97th Annual Meeting of the American Urological Association in Orlando, Florida.
That same year on November 2002, Cialis was approved in Europe. One year later Lilly and Icos finally won U.S. FDA approval for Cialis on November 21, 2003.
Tadalafil, brand name Cialis, has a distinct advantage over Viagra. Cialis drugs lasts up to 36 hour verses 4 hours for Viagra drugs. This can prove to be more appealing to most men and perhaps a better value. While Viagra enjoys better brand recognition Cialis will follow suit.
How does Cialis work?
When a man is sexually stimulated, signals from the nervous system and the release of chemical messengers within the tissues of the penis allow him to have an erection.
One of these chemical messengers, called cyclic GMP, causes the blood vessels in the penis to widen by relaxing smooth muscle tissue. This results in more blood flow to the penis, making the penis larger and harder until full erection.
Cyclic GMP is normally regulated and constantly broken down by another chemical in the body called PDE-5. When there is more cyclic GMP than PDE-5, an erection results. Once the PDE-5 breaks down the cyclic GMP, the erection goes away.
Men with ED often cannot produce enough cyclic GMP. The little that is made is rapidly broken down by PDE-5, and blood flow is reduced, resulting in erectile failure.
Cialis drug is a PDE-5 inhibitor. It works by preventing the action of PDE-5, therefore stopping the breakdown of cyclic GMP.
This means that the blood vessels are kept dilated for longer, improving and maintaining blood flow to the penis, and therefore magnifying the natural erectile function.
* It is important to understand that taking Cialis will not just make you have a sudden or unexpected erection at inappropriate times. What happens after taking Cialis drugs is that, if you are not sexually stimulated, your body will not produce any Cyclic GMP and PDE-5, and without those present in your body, Canadian Cialis will have nothing to work on and will therefore remain inactive. Similarly, after sex, as sexual stimulation stops, your body will stop the production of Cyclic GMP and PDE-5, and your erection will go away. Cheap Cialis will remain in your system for its duration, so if you are stimulated while it’s still present in your body, it will help you have and keep an erection.
Other drugs that operate the same way as Cialis are Viagra and Levitra.