Editing Sildenafil (section)

====European Union====
[[File:Sildenafil 100 milligram tablets - (prescription in the European Union) - Transgender shows the four-pack of 100 milligrams of tablet - Image 002n) - Transgender zeigt den Vierpack der je 100 Milligramm Tablette - Bild 002.jpg|thumb|upright=0.7|Sildenafil 100 milligram tablets (prescription in the European Union)]]
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.<ref>{{cite web|title=Actavis Launches Generic Viagra in Europe as Patents Expire|date=24 June 2013|url=https://finance.yahoo.com/news/actavis-launches-generic-viagra-r-120020258.html|access-date=25 October 2013|archive-date=29 October 2013|archive-url=https://web.archive.org/web/20131029201715/http://finance.yahoo.com/news/actavis-launches-generic-viagra-r-120020258.html|url-status=live}}</ref><ref name="What">{{cite web |url=http://www.accessrx.com/research/viagra-patent-expires |title=What Will Happen When Viagra Goes Generic? |vauthors=Edwards J |date=21 October 2009 |publisher=AccessRx.com |access-date=25 March 2011 |archive-date=23 April 2011 |archive-url=https://web.archive.org/web/20110423201812/http://www.accessrx.com/research/viagra-patent-expires |url-status=dead }}</ref><ref>{{cite news|title=Is Viagra about to lose its pulling power in the UK?|url=https://www.theguardian.com/business/shortcuts/2013/jun/03/viagra-lose-patent-pfizer-generic|newspaper=The Guardian|access-date=13 June 2013|date=3 June 2013|archive-date=30 October 2013|archive-url=https://web.archive.org/web/20131030182608/http://www.theguardian.com/business/shortcuts/2013/jun/03/viagra-lose-patent-pfizer-generic|url-status=live}}</ref> A UK patent held by Pfizer on the use of [[PDE5 inhibitor]]s (see below) as treatment of impotence was invalidated in 2000 because of [[Inventive step and non-obviousness|obviousness]]; this decision was upheld on appeal in 2002.<ref>{{cite news |url=https://www.telegraph.co.uk/money/main.jhtml?xml=/money/2002/01/24/cnviag24.xml |title=Viagra ruling upsets Pfizer |date=23 January 2002 |publisher=Telegraph Media Group Limited |access-date=10 February 2009 | location=London | vauthors = Murray R |url-status=dead |archive-url = https://web.archive.org/web/20090822222900/http://www.telegraph.co.uk/finance/2750418/Viagra-ruling-upsets-Pfizer.html|archive-date = 22 August 2009}}</ref><ref>{{cite web|url=http://www.urotoday.com/browse_categories/erectile_dysfunction/pfizer_loses_uk_battle_on_viagra_patent.html| title=Pfizer Loses UK Battle on Viagra Patent |date=17 June 2002 |publisher=Thomson Reuters |work=UroToday |access-date=10 February 2009|url-status = dead|archive-url = https://web.archive.org/web/20070625060239/http://www.urotoday.com/browse_categories/erectile_dysfunction/pfizer_loses_uk_battle_on_viagra_patent.html|archive-date = 25 June 2007}}</ref>