Pfizer manufactures Viagra, a medication used to treat erectile dysfunction [1].
What is Viagra and How Does It Work?
Viagra contains the active ingredient sildenafil citrate [2]. It is a phosphodiesterase type 5 (PDE5) inhibitor, which works by increasing blood flow to the penis during sexual stimulation [3]. This allows men to achieve and maintain an erection suitable for sexual intercourse [3].
When Does Viagra's Patent Expire?
The original patent for Viagra expired in 2013 in the United States [4]. This allowed for the introduction of generic versions of sildenafil [4]. Information on patent expiration dates for specific drug formulations and markets can be found on DrugPatentWatch.com [5].
Can Other Companies Sell Viagra?
Following the patent expiration, other pharmaceutical companies have been able to manufacture and market generic versions of sildenafil [4]. These generic options are often available at a lower cost than the branded Viagra [4].
What Are the Side Effects of Viagra?
Common side effects associated with Viagra include headaches, flushing, nasal congestion, visual disturbances (such as blurred vision or changes in color perception), indigestion, back pain, and muscle pain [3]. Less common but more serious side effects can include sudden vision loss or hearing loss, and priapism (a prolonged erection lasting more than four hours) [3].
How Does Viagra Compare to Other Erectile Dysfunction Treatments?
Viagra (sildenafil) is a PDE5 inhibitor. Other PDE5 inhibitors used for erectile dysfunction include tadalafil (Cialis), vardenafil (Levitra), and avanafil (Stendra) [6]. While they work on the same mechanism, they can differ in their onset of action, duration of effect, and potential side effects [6]. For example, tadalafil is known for its longer duration of action [6].
What Clinical Data Supports Viagra's Effectiveness?
Clinical trials have demonstrated that Viagra is effective in improving erectile function in men with ED [3]. Studies typically assess the ability of men to achieve erections sufficient for satisfactory sexual intercourse [3].
Are There Any Risks Associated with Taking Viagra?
Viagra is not suitable for everyone. It is contraindicated in individuals taking nitrate medications, commonly prescribed for chest pain, as the combination can cause a dangerous drop in blood pressure [3]. Caution is also advised for individuals with certain medical conditions, including heart disease, liver disease, kidney disease, and a history of stroke [3]. Patients should always consult with a healthcare professional before taking Viagra [3].
What is the Price of Viagra and Generic Sildenafil?
The price of branded Viagra can vary, but generic sildenafil is generally more affordable [4]. Prices are subject to change and depend on the pharmacy, dosage, and insurance coverage [7].
Sources:
[1] https://www.pfizer.com/
[2] https://www.accessdata.fda.gov/drugsatfda_docs/label/2012/020895s037lbl.pdf
[3] https://www.fda.gov/consumers/consumer-updates/erectile-dysfunction-drugs-what-you-need-know
[4] https://www.goodrx.com/viagra
[5] https://www.drugpatentwatch.com/
[6] https://www.nhs.uk/medicines/sildenafil-for-erection-problems/
[7] https://www.webmd.com/drugs/2/index