"Efficacy and safety of sildenafil treatment in pulmonary arterial hypertension: a systematic review". Archived from the original on 29 August 2021. "Raynaud's phenomenon and digital ischaemia--pharmacologic approach and alternative treatment options". "Efficacy of Sildenafil on healthy humans in high‑altitude hypoxia at rest and during exercise: A meta‑analysis". "Interventions for preventing high altitude illness: Part 1.
What is sildenafil?
"With Viagra Now Available Over-The-Counter In The U.K., Will The U.S. "Phosphodiesterase inhibitors for erectile dysfunction in patients with diabetes mellitus". "Strategies for managing sexual dysfunction induced by antidepressant medication". The Cochrane Database of Systematic Reviews (5) CD003382. Archived from the original on 10 October 2020. Archived from the original on 10 June 2017.
- OTC Sildenafil products may contain counterfeit or substandard ingredients.
- Many OTC Sildenafil products are marketed as quick fixes for erectile issues.
- The availability of OTC Sildenafil has increased with online shopping.
- OTC Sildenafil use outside medical supervision can be dangerous.
- Some OTC formulations include herbal or natural ingredients with Sildenafil.
- The safety of OTC Sildenafil depends heavily on manufacturing practices.
- Potential side effects include headaches, dizziness, and blood pressure changes.
- OTC Sildenafil should be avoided by those with certain health conditions.
- Always read labels carefully before purchasing OTC Sildenafil.
- OTC Sildenafil can interact with medications like nitrates, causing hypotension.
- Seek medical advice before starting OTC Sildenafil treatments.
^ "FDA Updates Labeling for Viagra, Cialis and Levitra for Rare Post-Marketing Reports of Eye Problems" (Press release).
| Product | Dosage | Quantity + Bonus | Price | |
|---|---|---|---|---|
| Kamagra Oral Jelly | 100mg | 21 Sachets | 95.92€ 91.35€ | |
| Viagra Generic | 25mg | 270 + 8 Pills | 184.26€ 175.49€ | |
| Viagra Generic | 150mg | 10 Pills | 36.73€ 34.98€ | |
| Kamagra Oral Jelly | 100mg | 110 + 9 Sachets | 334.87€ 318.92€ | |
| Viagra Generic | 100mg | 120 + 6 Pills | 149.50€ 142.38€ | |
| Viagra Generic | 25mg | 180 + 6 Pills | 154.93€ 147.55€ | |
| Viagra Generic | 50mg | 10 Pills | 26.87€ 25.59€ | |
| Viagra Generic | 150mg | 90 + 6 Pills | 147.18€ 140.17€ | |
| Viagra Generic | 100mg | 180 + 8 Pills | 199.37€ 189.88€ | |
| Viagra Generic | 50mg | 270 + 8 Pills | 198.48€ 189.03€ | |
| Kamagra Oral Jelly | 100mg | 30 + 5 Sachets | 136.20€ 129.71€ | |
| Kamagra Soft Tabs | 100mg | 12 Pills | 57.55€ 54.81€ | |
| Kamagra Polo | 100mg | 20 Pills | 83.56€ 79.58€ | |
| Kamagra Polo | 100mg | 180 + 8 Pills | 446.52€ 425.26€ | |
| Kamagra Soft Tabs | 100mg | 20 Pills | 79.79€ 75.99€ | |
| Viagra Generic | 25mg | 30 + 4 Pills | 47.97€ 45.69€ |
Archived from the original on 22 October 2016. "Vision disorders and phosphodiesterase type 5 inhibitors: a review of the evidence to date". ^ "FDA Announces Revisions to Labels for Cialis, Levitra and Viagra". "Drug interactions with phosphodiesterase-5 inhibitors used for the treatment of erectile dysfunction or pulmonary hypertension".
- Many OTC "herbal" formulas claim to enhance sexual performance containing Sildenafil.
- OTC Sildenafil products are sometimes sold as libido boosters for men.
- Buyers should verify the legitimacy of OTC products claiming to contain Sildenafil.
- OTC Sildenafil may be found in health stores or online pharmacies.
- It's important to check for FDA or equivalent approval before purchasing OTC Sildenafil.
- OTC Sildenafil often lacks clear dosage information on packaging.
- The risk of drug interactions increases with OTC Sildenafil from unknown sources.
- Some OTC formulations contain undeclared Sildenafil, posing health risks.
- OTC Sildenafil use without medical supervision can lead to adverse events.
- Psychoactive effects may occur if OTC Sildenafil is combined with other drugs.
- OTC Sildenafil can cause priapism if used improperly and in high doses.
"Pharmacology and drug interaction effects of the phosphodiesterase 5 inhibitors: focus on alpha-blocker interactions". Use of sildenafil (Viagra) in patients with cardiovascular disease.
5.3 Effects on the Eye
Archived from the original on 12 October 2020. ^ "Viagra 25mg film-coated tablets Summary of Product Characteristics (SmPC)". ^ "Viagra Connect 50 mg film-coated tablets Summary of Product sildenafil pfizer 100g Characteristics (SmPC)". Archived from the original on 13 August 2020. Archived from the original on 11 October 2020.
What everyday foods contain PDE5 inhibitors?
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.
Sildenafil Tablets for ED
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". Archived from the original on 31 March 2021. American College of Cardiology/American Heart Association".
| Precaution / Contraindication | Explanation | Alternative Actions or Notes |
|---|---|---|
| Use with nitrates | Dangerous, can cause severe hypotension | Seek medical advice |
| Heart conditions | May worsen certain conditions | Consult doctor before use |
| Alcohol consumption | Can increase side effects or reduce efficacy | Limit alcohol intake |
| Interactions with other meds | Potential for adverse interactions | Review all medications with a healthcare provider |
Journal of the American College of Cardiology. ^ "Viagra (Sildenafil Citrate): Side Effects, Interactions, Warning, Dosage & Uses". Archived from the original on 12 July 2018. "Young men add Viagra to their drug arsenal".
| Country | OTC Availability | Regulations/Restrictions | Notes |
|---|---|---|---|
| USA | Some products | FDA regulations, claims must be substantiated | Limited to specific formulations |
| UK | Allowed in pharmacies | MHRA regulations, age restrictions | Mix of OTC and behind-the-counter |
| Australia | Restricted | TGA approvals needed, pharmacy sales | Limited brands, professional advice |
| Canada | Available | Health Canada approval, OTC or behind-the-counter | Varies by province |
Archived from the original on 4 September 2014.
| Parameter | Description | Typical Values | Notes |
|---|---|---|---|
| Absorption Time | Time to reach peak plasma concentration | 30-120 minutes | Varies with formulation |
| Half-life | Duration of drug's effect | 4-6 hours | Clearance processed mainly by liver |
| Bioavailability | Percentage of active drug absorbed into bloodstream | ~40-50% | Affected by food intake |
"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).
Detection in biological fluids
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.
Viagra Soft Tabs
[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.
Black ginger
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. "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?".
Brand names
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. 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.
Upcoming Events
In the US, Revatio and Viagra are marketed by Viatris after Upjohn was spun off from Pfizer. In Canada, Pfizer's patent 2,324,324 for Revatio (sildenafil used to treat pulmonary hypertension) was found invalid by the Federal Court in June 2010, on an application by Ratiopharm Inc.[106][107] On 8 November 2012, the Supreme Court of Canada ruled that Pfizer's patent 2,163,446 on Viagra was invalid from the beginning because the company did not provide full disclosure in its application. The decision, Teva Canada Ltd. v. Pfizer Canada Inc., pointed to section 27(3)(b) of The Patent Act which requires that disclosure must include sufficient information "to enable any person skilled in the art or science to which it pertains" to produce it.
Avanafil (Stendra)
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.
Horny goat weed
[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. "Bears' Brandon Marshall says some NFL players use Viagra .. on the Field".
- Overuse of OTC Sildenafil can lead to unwanted side effects and health risks.
- OTC Sildenafil is not approved by medical authorities for general use.
- Pharmacovigilance agencies monitor adverse effects from OTC Sildenafil.
- OTC Sildenafil may contain other undisclosed active substances.
- Always check for proper labeling when purchasing OTC Sildenafil.
- OTC Sildenafil should not be used as a recreational drug.
- Consumers should be aware of potential health hazards of OTC Sildenafil.
- OTC Sildenafil may impair blood pressure regulation in some users.
- Regular use of OTC Sildenafil without medical oversight is risky.
- Using OTC Sildenafil with alcohol can increase side effects.
- OTC Sildenafil is often advertised with exaggerated claims of effectiveness.
Archived from the original on 5 March 2016.
8.2 Lactation
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.
Viagra Brand
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.
Tadalis Sx
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. "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". Archived from the original on 4 March 2016.