Who Invented Viagra?

Viagra and the patenting of an aphrodisiac.

Bottles of Viagra
Bottles of Viagra. Getty Images News

According to the British Press, Peter Dunn and Albert Wood are named as the inventors of the process by which Viagra was created. Their names appeared on an application by Pfizer to patent (WOWO9849166A1) the manufacturing process of Sildenafil Citrate, better known as Viagra.

Peter Dunn and Albert Wood are both employees of Pfizer Pharmaceuticals at the Pfizer run research laboratories in Kent and thus are not allowed to discuss their status or non-status as inventors.

In a statement Albert Wood said: "I can't say anything, you'll have to talk to the press office..."

On the invention of Viagra, a Pfizer Pharmaceuticals spokesperson said:

"Life might seem cruel, but they are paid to work for the company and the company owns their inventions. Literally hundreds of people at Pfizer have been involved in developing the drug. You can't really point to two individuals and say they spawned Viagra."

More of a Team Effort 

Anyhow, to the best of our knowledge, this is how the story goes. In 1991, inventors Andrew Bell, Dr. David Brown and Dr. Nicholas Terrett discovered that chemical compounds belonging to the pyrazolopyrimidinone class were useful in treating heart problems such as angina. Some experts consider Terrett as the father of Viagra as he was named in the 1991 British patent for Sildenafil (tradenamed Viagra) as a possible heart medicine.

It was in I994, though, that Terrett and his colleague Peter Ellis discovered during the trial studies of Sildenafil as a potential heart medication that it also increased blood flow to the penis, allowing men to reverse erectile dysfunctions.

The drug acts by enhancing the smooth muscle relaxant effects of nitric oxide, a chemical that is normally released in response to sexual stimulation. The smooth muscle relaxation allows increased blood flow into the penis, leading to an erection when combined with something arousing.

While Terrett is not allowed to discuss whether he considers himself the real inventor of Viagra as he is still a Pfizer employee, he did once state: "There were three patents put forward for Viagra.

Basically me and my team discovered how useful the drug might be... they (Wood and Dunn) created a way of mass producing it only." 

Pfizer claims that hundreds of inventors were involved with the creation of Viagra and that there was not enough room on the patent application to name them all. Thus, only the department heads were listed. Dr. Simon Campbell, who until recently was the Senior Vice President Of Medicinal Discovery at Pfizer and oversaw Viagra's development, is considered by the American press to be the inventor of Viagra. However, Campbell would rather be remembered as the father of Amlodipine, a cardiovascular drug. 

Steps In Making Viagra

Dunn and Wood worked on the crucial nine-step process to synthesize a Sildenafil (Viagra) compound into a pill. It was approved by the FDA on March 27, 1998 as the first pill to treat impotence. Here is a quick summary of the steps:

  1. Methylation of 3-propylpyrazole-5-carboxylic acid ethyl ester with hot dimethyl sulfate
  2. Hydrolysis with aqueous NaOH to free acid
  3. Nitration with oleum/fuming nitric acid
  4. Carboxamide formation with refluxing thionyl chloride/NH4OH
  5. Reduction of nitro group to amino
  6. Acylation with 2-ethoxybenzoyl chloride
  7. Cyclization
  1. Sulfonation to the chlorosulfonyl derivative
  2. Condensation with 1-methylpiperazine

Empirical formula = C22H30N6O4S
molecular weight = 474.5
solubility = 3.5 mg/mL in water

Viagra and Lawsuits

One billion dollars in sales were made in Viagra's first year of production. But soon many lawsuits against Viagra and Pfizer were filed. This included a suit filed for $110 million dollars on behalf of Joseph Moran, a car dealer from New Jersey. He claimed that he crashed his car into two parked cars after Viagra caused him to see blue lightning coming from his fingertips, at which point he blacked out. Joseph Moran was driving his Ford thunderbird home after a date at the time.

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Bellis, Mary. "Who Invented Viagra?" ThoughtCo, Oct. 29, 2017, thoughtco.com/viagra-1992596. Bellis, Mary. (2017, October 29). Who Invented Viagra? Retrieved from https://www.thoughtco.com/viagra-1992596 Bellis, Mary. "Who Invented Viagra?" ThoughtCo. https://www.thoughtco.com/viagra-1992596 (accessed November 21, 2017).