OTTAWA - Canada's market for generic erectile dysfunction drugs was thrown open for business Thursday after the Supreme Court of Canada invalidated the Viagra patent held by the pharmaceutical giant Pfizer.

Hours after Teva Canada, the Canadian drug company, won its appeal before the high court, it posted notice of its own generic version on its website — the first commercial challenge to Pfizer's 14-year Viagra monopoly.

The Supreme Court, in an unanimous 7-0 ruling, annulled Pfizer's Viagra patent, saying it tried to "game" the Canadian system. The high court sided with Teva Canada's challenge of the legitimacy of the patent, paving the way for cheaper, generic versions.

The decision has big implications for users of erectile dysfunction drugs and the pharmaceutical industry because it allows companies to create generic versions that are usually cheaper for consumers.

Teva pledged Thursday to sell its new generic version of the drug at a "significantly lower" cost than Viagra.

Company president Barry Fishman said in a statement that his company's new generic drug "will not only result in millions in savings to consumers, but it will make this medication accessible to people who might otherwise (have) not been able to afford it."

Teva's website featured a notice entitled, "Introducing Novo-Sildenafil," a product it described as was "a generic alternative to Viagra."

The notice contained few other details, except to say the company's products are available by prescription and that patients and customers are encouraged to discuss their options with health care practitioners.

"Canadian consumers will be saving money on it. There will probably be other generics involved soon enough," said Richard Gold, an intellectual property expert at Montreal's McGill University.

The ruling wipes out Pfizer's market dominance with Viagra. Its patent was scheduled to expire in 2014.

Pfizer said it was disappointed with the ruling.

"Pfizer expects to face generic competition in Canada shortly," the company said in a statement issued by its New York office. "Pfizer will continue to vigorously defend against challenges to its intellectual property."

The case also has broad commercial implications for patent law.

The Patent Act gives a company a 16-year monopoly on a product if it can prove it is a new invention. In return, the company must show publicly in its application how it created its product, so others can copy it later.

"Pfizer gained a benefit from the act — exclusive monopoly rights — while withholding disclosure in spite of its disclosure obligations under the act," Justice Louis LeBel wrote on behalf of the court.

"As a matter of policy and sound statutory interpretation, patentees cannot be allowed to 'game' the system in this way. This, in my view, is the key issue in this appeal.

"Pfizer had the information needed to disclose the useful compound and chose not to release it."

This case turned on whether Pfizer deliberately thwarted Teva's ability to copy the key chemical compound of the drug.

Teva challenged the validity of the Pfizer patent, claiming it did not meet the law's disclosure requirements.

In its original patent application, Pfizer listed a staggering number of chemical compounds, but didn't specify which one actually worked — sildenafil.

Pfizer obtained the patent in 1998 after applying four years earlier. It was first challenged by the generic drug maker in 2007.

Teva originally questioned Pfizer's patent in Federal Court and the Federal Court of Appeal, but lost at both levels.

The ruling sends a strong message to future patent applicants that "gaming" the system will no longer work, said Gold.

"This is particularly important in the pharmaceutical industry where both brand name and generic companies play games, wasting court resources and putting money into litigation rather than into actual research."

Gold said in recent years several large companies have shut down their research and development branches in the Canadian pharmaceutical industry.

"This is a good day for Canadian patent law, for Canadian courts and for Canadians," he said. "With this clear signal, the court has put the focus of the patent system back on innovation and away from game playing and strategy that only harms Canadians."

In its statement, Pfizer said the patent process spurs innovation.

"Patents provide a vital incentive for biopharmaceutical companies to invest in new and life-saving medicines that benefit millions of patients worldwide. At Pfizer, we apply science and our global resources to improve health and well-being at every stage of life."

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  • Keeps Your Blood Flowing

    According to Dr. Jennifer Berman, co-founder of the Female Sexual Medicine Center at UCLA, orgasms increase your circulation, keeping the blood flowing to your genital area. This in turn keeps your tissue healthy!

  • It's A Form Of Cardio

    Although it can't be considered an alternative to daily exercise, having an orgasm is a cardiovascular activity. "Your heart rate increases, blood pressure increases [and your] respiratory rate increases," says Berman. And because it's akin to running in many physiological respects, your body also releases endorphins. Sounds like a pretty fun way to work your heart out.

  • Lifts Your Mood

    Feeling down in the dumps? An orgasm might be just what you need to pick yourself up. In addition to endorphins, dopamine and oxytocin are also released during orgasm. All three of these hormones have what Berman terms "mood-enhancing effects." In fact, dopamine is the same hormone that's released when individuals use drugs such as cocaine -- or eat something really delicious.

  • Helps You Sleep

    A little pleasure may go a long way towards a good night's rest. A recent survey of 1,800 women found that over 30 percent of them used sexual release as a natural sedative.

  • Keeps Your Brain Healthy

    Having an orgasm not only works out your heart, but also your head. Barry Komisaruk, Ph.D. <a href="http://www.cosmopolitan.com/sex-love/tips-moves/orgasm-news" target="_hplink">told <em>Cosmopolitan</em></a> that orgasms actually nourish the brain with oxygen. "Functional MRI images show that women's brains utilize much more oxygen during orgasm than usual," Komisaruk says.

  • It's A Natural Painkiller

    One thing that Victorian practitioners may have been onto is that orgasms can work to soothe certain aches and pains -- namely migraines and menstrual cramps. (So now you know what to do next time you have a headache if you don't feel like popping an Excedrin.) According to Berman, the contractions that make up an orgasm can actually work to evacuate blood clots during your period, providing some temporary relief.

  • It Relieves Stress

    Most of our lives are so hectic that it's hard to even imagine being relaxed. However, it turns out that <em>sexual</em> release can double as <em>stress</em> relief. Not only do the hormones help with this task, Berman says that being sexual also gives our minds a break: "When we're stressed out and overextending ourselves, [we're] not being in the moment. Being sexual requires us to focus on one thing only."

  • Gives You A Healthy Glow

    There actually might be something to the idea that we "glow" after sex. The hormone DHEA (dehydroepiandrosterone), which shows <a href="http://www.ivillage.com/secret-health-benefits-sex/4-a-283856" target="_hplink">increased levels during sexual excitement</a>, can actually make your skin healthier.

  • Aids Your Emotional Health

    Last but not least, when you know what it takes to make yourself orgasm, you may increase your emotional confidence and intelligence. "When you understand how your body works and ... [that it] is capable of pleasure on its own, regardless of your partner status, you make much better decisions in relationships," says Logan Levkoff, Ph.D., a sexologist and certified sexuality educator. "You don't look to someone else to legitimize that you're a sexual being."