Food and Drug Administration (FDA). Archived from the original on 31 sildenafil 50g March 2021. Archived from the original on 12 August 2025. ^ "Sildenafil Drug Usage Statistics, United States, 2014 - 2023". "Generic Viagra: Two versions of sildenafil hit the market today". Archived from the original on 25 November 2018. Archived from the original on 12 February 2022. "With Viagra Now Available Over-The-Counter In The U.K., Will The U.S.
Manufacture and sale of sildenafil citrate drugs known as "generic Viagra" is common in India, where Pfizer's patent claim does not apply. Brand names include Kamagra (Ajanta Pharma), Silagra (Cipla), Edegra (Sun Pharmaceutical), Penegra (Zydus Cadila), Manly (Cooper Pharma) and Zenegra (Alkem Laboratories). Sildenafil was reclassified in New Zealand in 2014 so it could be bought over the counter from a pharmacist. It is thought that this reduced sales over the Internet and was safer as males could be referred for medical advice if appropriate. In 1999 South Korea granted two patents to Pfizer related to sildenafil.
The first document guaranteed sole production and sale of the substance until 2012, while the second gave Pfizer the exclusive use to treating erectile dysfunction with sildenafil until 2014. [123] In 2011 Hanmi Pharmaceutical and CJ CheilJedang launched a suit against the exclusive use patent. The Korean Court system made a ruling against Pfizer in June 2012, allowing for the unhindered domestic production of generic prescription sildenafil. In 2012, Viagra lost its position as the top selling erectile dysfunction treatment in South Korea. This development was credited largely "due to the introduction of generic products." Generic sildenafil became publicly available in May. "Phosphodiesterase inhibitors for erectile dysfunction in patients with diabetes mellitus". "Strategies for managing sexual dysfunction induced by antidepressant medication".
| Product | Dosage | Quantity + Bonus | Price | |
|---|---|---|---|---|
| Kamagra | 100mg | 180 + 6 Pills | 436.79€ 415.99€ | |
| Kamagra Soft Tabs | 100mg | 32 Pills | 120.11€ 114.39€ | |
| Viagra Generic | 50mg | 270 + 8 Pills | 198.48€ 189.03€ | |
| Viagra Generic | 150mg | 90 + 6 Pills | 147.18€ 140.17€ | |
| Viagra Generic | 200mg | 60 + 4 Pills | 125.19€ 119.23€ | |
| Viagra Generic | 200mg | 180 + 10 Pills | 277.56€ 264.34€ | |
| Viagra Generic | 150mg | 360 + 10 Pills | 423.48€ 403.31€ | |
| Viagra Generic | 200mg | 360 + 10 Pills | 481.98€ 459.03€ | |
| Viagra Generic | 25mg | 20 Pills | 37.74€ 35.94€ | |
| Viagra Generic | 50mg | 10 Pills | 26.87€ 25.59€ | |
| Kamagra Polo | 100mg | 272 + 12 Pills | 622.94€ 593.28€ | |
| Viagra Generic | 150mg | 30 + 2 Pills | 72.32€ 68.88€ | |
| Viagra Generic | 25mg | 180 + 6 Pills | 154.93€ 147.55€ | |
| Kamagra Oral Jelly | 100mg | 21 Sachets | 95.92€ 91.35€ | |
| Viagra Generic | 50mg | 120 + 6 Pills | 129.64€ 123.47€ |
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Archived from the original on 11 November 2020. ^ Nichols DJ, Muirhead GJ, Harness JA (6 March 2002). "Pharmacokinetics of sildenafil after single oral doses in healthy male subjects: absolute bioavailability, food effects and dose proportionality". The American Society of Health-System Pharmacists. Archived from the original on 23 April 2020.
PDE-5 inhibitors appear to have significant but moderate efficacy in secondary [Raynaud's phenomenon]. "Sublingual sildenafil in the treatment of erectile dysfunction: faster onset of action with less dose". "The Serendipitous Story of Sildenafil: An Unexpected Oral Therapy for Erectile Dysfunction". ^ "Drug Approval Package: Viagra (sildenafil citrate) NDA #020895". U.S. American College of Cardiology/American Heart Association". Journal of the American College of Cardiology.
Sales of PalPal by Hanmi Pharmaceuticals totalled ₩22 billion or about 86% the market share of Viagra that year. [125] By 2017, there were over 50 generic sildenafil pills available. During that year Viagra sales slumped to 38% that of Palpal. There were 2,958,199 prescriptions for Sildenafil in 2016 in England, compared with 1,042,431 in 2006. In 2018, Viagra Connect, a particular formulation of Sildenafil marketed by Pfizer, became available for sale without a prescription in the UK.
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It added further: "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. Teva Canada launched Novo-Sildenafil, a generic version of Viagra, on the day the Supreme Court of Canada released its decision. [109][110][111] To remain competitive, Pfizer then reduced the price of Viagra in Canada. [112] However, on 9 November 2012, Pfizer filed a motion for a re-hearing of the appeal in the Supreme Court of Canada,[113] on the grounds that the court accidentally exceeded its jurisdiction by voiding the patent.
[114] Finally, on 22 April 2013, the Supreme Court of Canada invalidated Pfizer's patent altogether. Manufacture and sale of sildenafil citrate drugs is common in China, where Pfizer's patent claim is not widely enforced. Egypt approved Viagra for sale in 2002, but soon afterwards allowed local companies to produce generic versions of the drug, citing the interests of poor people who would not be able to afford Pfizer's price. In June 2013 Pfizer's patent on sildenafil citrate expired in some member countries of the European Union, including Austria, Denmark, France, Germany, Ireland, Italy, The Netherlands, Spain, Sweden, the United Kingdom, and Switzerland. [117][118][119] A UK patent held by Pfizer on the use of PDE5 inhibitors (see below) as treatment of impotence was invalidated in 2000 because of obviousness; this decision was upheld on appeal in 2002. "Young men add Viagra to their drug arsenal". Archived sildenafil citrate chewable tablets from the original on 4 September 2014. "Recreational use and misuse of phosphodiesterase 5 inhibitors". Archived from the original on 21 August 2016. "Sildenafil does not improve sexual function in men without erectile dysfunction but does reduce the postorgasmic refractory time". ^ McCambridge J, Mitcheson L, Hunt N, Winstock A (March 2006). "The rise of Viagra among British illicit drug users: 5-year survey data". "Does marijuana use play a role in the recreational use of sildenafil?". Archived from the original on 26 January 2013. "Sildenafil accelerates reentrainment of circadian rhythms after advancing light schedules". Proceedings of the National Academy of Sciences of the United States of America. "Source: Roger Clemens, host of athletes pop Viagra to help onfield performance". Archived from the original on 14 August 2020. "Bears' Brandon Marshall says some NFL players use Viagra .. on the Field". Archived from the original on 5 March 2016. "Towards a decade of detecting new analogues of sildenafil, tadalafil and vardenafil in food supplements: a history, analytical aspects and health risks". "Detection of sildenafil analogues in herbal products for erectile dysfunction".
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| Country | Status | Patents Expiry | Notes |
|---|---|---|---|
| United States | Off-patent | 2013 | Widely available as generic |
| India | Approved | N/A | Production of multiple brands |
| Europe | Generic approved | 2012 | Several authorized companies |
| Australia | Prescription only | N/A | Available via prescription |
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