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Medical Use and Dosage Details

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. sale of the substance until 2012, while

the second gave Pfizer the exclusive use

to treating erectile dysfunction

with sildenafil until 2014.

• Sildenafil 120 mg is not approved by all regulatory agencies for general use.
• The maximum recommended dose for most individuals is 100 mg.
• Using high doses can lead to increased cardiovascular strain.
• Always inform your doctor of all medications to prevent interactions.
• Sildenafil may cause a sudden drop in blood pressure, especially with certain drugs.
• The medication can be used as part of a treatment plan for erectile dysfunction.

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• Side effects from high doses may include dizziness, flushing, or stomach upset.
• The onset of action is typically within 30 to 60 minutes after intake.
• Patients should avoid heavy meals before taking sildenafil for quicker results.
• Overdose symptoms include chest pain, loss of vision, and fainting.
• Sildenafil is not a cure for erectile dysfunction but enhances blood flow temporarily.
• Medical review is crucial for safety when considering high-dose sildenafil.

Pharmaceutical and CJ CheilJedang

Overdose/Missed Dose

In 1992, Pfizer filed a patent covering the substance sildenafil and its use to treat cardiovascular diseases. [96] This would be marketed as Revatio. The patent was published in 1993 and expired in 2012. The patent on Revatio (indicated for pulmonary arterial hypertension rather than erectile dysfunction) expired in late 2012. Generic versions of this low-dose form of sildenafil have been available in the US from a number of manufacturers, including Greenstone, Mylan, and Watson, since early 2013.

5. Target Countries and Export Markets

[97] Health care providers may prescribe generic sildenafil for erectile dysfunction. [98] For a time, the generic was not available in the same dosages as branded Viagra, so using dosages typically required for treating ED required patients to take multiple pills. In 1994, Pfizer filed a patent covering the use of sildenafil to treat erectile dysfunction. [99] This would be marketed as Viagra. This patent was published in 2002 and expired in 2019.

Before taking sildenafil,

Teva sued to have the latter patent invalidated, but Pfizer prevailed in an August 2011 federal district court case. [100] An agreement with Pfizer allowed Teva to begin to provide the generic drug in December 2017. In the United States, Pfizer received two patents for sildenafil: one for its indication to treat cardiovascular disease (marketed as Revatio) and another for its indication to treat erectile dysfunction (marketed as Viagra). The substance is the same under both brand names. Sildenafil is available as a generic drug in the United States, labeled for pulmonary arterial hypertension,[98] and to treat erectile dysfunction, as the patent expired in April 2020. launched a suit against the exclusive use patent.

5.7 Combination with other PDE5 Inhibitors or Other Erectile Dysfunction Therapies

[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.