Archived from the original on 6 December 2017. "Why Pfizer Is About to Slash Viagra's Price in Half". Archived from the original on 7 December 2017. "Pfizer to lose patent of drug Viagra, Indian companies gear up with copycat versions: Pfizer's patent for the formulation of Viagra, used to treat impotence in men, ends in the US in 2020". Archived from the original on 17 April 2021. ^ "Set to conquer US, Indian 'Viagras' may give Pfizer a hard Time". Archived from the original on 22 December 2020. ^ a b "Pfizer Settles Viagra® Patent Litigation With Teva". "Lockout Supplements Issues Voluntary Nationwide Recall of Boner Bears Chocolate Syrup Due to Undeclared Sildenafil". Archived from the original on 19 November 2016.

• Sildenafil is metabolized primarily by the liver enzyme CYP3A4.
• Drugs that inhibit this enzyme can increase sildenafil levels and side effects.
• Examples include some antibiotics, antifungals, and HIV medications.
• Drugs that induce CYP3A4 can decrease sildenafil's effectiveness.
• Always provide your doctor with a complete list of your medications.
• This includes over-the-counter drugs, herbs, and supplements.
• Pharmacists perform interaction checks before dispensing.

"Counterfeit Viagra, Cialis, Levitra: The Ultimate Guide". Archived from the original on 10 January 2017.

Drug Class	Common Drugs	Effect	Notes
Nitrates	Nitroglycerin	Severe hypotension	Contraindicated
Alpha-blockers	Tamsulosin, Doxazosin	Increased hypotensive effect	Use with caution, start at lowest dose
CYP3A4 inhibitors	Ketoconazole, Itraconazole	Increased sildenafil levels	May increase side effect risk
Other ED medications	Tadalafil, Vardenafil	Enhanced effect	Risk of hypotension

"Online pharmacies suspected of counterfeit drug sales". ^ "Erectile Dysfunction Medication the Most Seized Drug During Global Crackdown, Interpol Says". ^ "Global illicit medicines targeted by INTERPOL operation". Archived from the original on 10 December 2023. ^ "Israeli-made AI exposes international fake Viagra network". ^ "Counterfeit Viagra Pills, Footwear, Belts, Car Emblems and Headphones Worth over $32 Million Seized at the LA/Long Beach Seaport U.S. Customs and Border Protection". Archived from the original on 12 October 2013. "Yes, There Is a Way to Get Generic Viagra".

Product 1. PRZ-sildenafil by Pharmaris Canada

Archived from the original on 9 January 2009. Archived from the original on 22 February 2021. ^ a b "Viagra sildenafil citrate tablets 150 mg now available over the counter without prescription in the UK". Archived from the original on 26 March 2021. Archived from the original on 8 December 2013.

Licensed practitioner consultation

"The coming generics threat to Pfizer's Viagra brand just got scarier". Archived from the original on 9 September 2017. ^ "Viagra to go generic in 2017 according to Pfizer agreement". Archived from the original on 1 December 2017. "Sex, Drugs and That Little Blue Pill". Archived from the original on 2 May 2016. "Pfizer Wins Viagra Patent Infringement Case Against Teva Pharmaceuticals". Archived from the original on 11 January 2015. ^ "Pfizer Completes Transaction to Combine Its Upjohn Business with Mylan". Retrieved 17 June 2024 – via Business Wire. Archived from the original on 17 June 2024. "Viagra patent expires in June, says Brazilian court". Archived from the original on 17 April 2012. ^ "Revatio patent ruled invalid for lack of sound prediction and obviousness". Archived from the original on 3 March 2016. {{cite web}}: CS1 maint: deprecated archival service (link) ^ Teva Canada Ltd. v. Pfizer Canada Inc., 2012 SCC 60 at par. "Supreme Court ruling could lead to cheaper versions of Viagra". Archived from the original on 10 March 2013. "Canadian Supreme court rules Viagra patent invalid". Archived from the original on 11 November 2012.

Product	Dosage	Quantity + Bonus	Price
Kamagra Soft Tabs	100mg	60 + 4 Pills	180.59€ 171.99€	Buy
Viagra Generic	100mg	30 + 4 Pills	60.91€ 58.01€	Buy
Kamagra Polo	100mg	32 Pills	125.88€ 119.89€	Buy
Viagra Generic	100mg	120 + 6 Pills	149.50€ 142.38€	Buy
Viagra Generic	100mg	10 Pills	28.91€ 27.53€	Buy
Viagra Generic	150mg	10 Pills	36.73€ 34.98€	Buy
Kamagra	100mg	32 Pills	121.24€ 115.47€	Buy
Viagra Generic	100mg	360 + 10 Pills	330.21€ 314.49€	Buy
Kamagra Soft Tabs	100mg	12 Pills	57.55€ 54.81€	Buy
Kamagra Polo	100mg	84 + 4 Pills	244.49€ 232.85€	Buy
Viagra Generic	200mg	120 + 8 Pills	204.80€ 195.05€	Buy
Kamagra Oral Jelly	100mg	90 + 8 Sachets	303.56€ 289.10€	Buy
Kamagra	100mg	60 + 4 Pills	201.34€ 191.75€	Buy
Viagra Generic	100mg	270 + 10 Pills	270.47€ 257.59€	Buy
Viagra Generic	200mg	20 Pills	61.69€ 58.75€	Buy

^ "Viagra patent tossed out by Supreme Court: Decision allows generic versions of drug to be produced". Archived from the original on 18 September 2013. ^ "Pfizer Canada drops Viagra price after generic versions get Supreme Court green light". Archived from the original on 30 November 2012. Archived from sildenafil citrate tablets 50 mg the original on 27 December 2013. "In rare move, Pfizer asks Supreme Court to reconsider ruling that killed Viagra patent". Archived from the original on 5 February 2013. "The Supreme Court of Canada holds Pfizer's Viagra patent invalid". Archived from the original on 20 May 2013.

Does viagra help with premature ejaculation

^ Boolell M, Allen MJ, Ballard SA, Gepi-Attee S, Muirhead GJ, Naylor AM, et al. "Sildenafil: an orally active type 5 cyclic GMP-specific phosphodiesterase inhibitor for the treatment of penile erectile dysfunction". "Sildenafil (Viagra), a potent and selective inhibitor of Type 5 cGMP phosphodiesterase with utility for the treatment of male erectile dysfunction". "Drug repositioning: identifying and developing new uses for existing drugs". Archived from the original on 22 April 2019.

Regional issues

Archived from the original on 10 June 2019. "Health situation in former communist bloc is dire, says Unicef". Archived from the original on 1 November 2012. ^ Gurevich M, Cormier N, Leedham U, Brown-Bowers A (August 2018). Sexuopharmaceutical use by men as prevention and proficiency". ^ "Actavis Launches Generic Viagra in Europe as Patents Expire". Archived from the original on 29 October 2013. "What Will Happen When Viagra Goes Generic?".

Status	Description	Legal Regulations
Prescription-Only	Must be prescribed by a licensed doctor	Controlled drug under Health Canada
OTC Availability	Not available over-the-counter in Canada	Requires medical consultation
Import Regulations	Personal import allowed with prescription	Customs may scrutinize unapproved imports
Patent Status	Patent expired in Canada (~2013)	Generic versions available

Archived from the original on 23 April 2011. ^ "Is Viagra about to lose its pulling power in the UK?". Archived from the original on 30 October 2013. Archived from the original on 22 August 2009. Archived from the original on 25 June 2007. "Viagra from the pharmacist: insight from reclassification in New Zealand". Archived from the original on 17 May 2021. ^ "Generic Viagra developers queue up, but may have to wait". Archived from the original on 28 December 2021.

• The patent expiration allowed multiple companies to produce generics.
• This increased competition, leading to lower prices for consumers.
• Generic drug approval in Canada requires proof of bioequivalence.
• The Patented Medicine Prices Review Board (PMPRB) regulates brand-name prices.
• Generic substitution by pharmacists is a common, accepted practice.
• Patients can request either the brand or generic, subject to coverage.
• The market is consistently supplied by numerous manufacturers.

^ "Approved Viagra copies flood drugstores in Korea". ^ "Viagra prescriptions almost triple in a decade".

What are common side effects of Sildenafil?

"Spreading the Word, but What Word is That? Viagra and Male Sexuality in Popular Culture". "A new view of women's sexual problems: Why new? Archived from the original on 3 January 2009. Archived from the original on 12 October 2008.

Drug Interactions

"Sales of Impotence Drugs Fall, Defying Expectations". Archived from the original on 11 October 2007. ^ "Pfizer Courting More Controversy with Viagra 'Advergaming'". Archived from the original on 19 December 2019. Archived from the original on 6 May 2018. Archived from the original on 1 July 2024. ^ sildenafil 100 mg cost "MHRA reclassifies Viagra Connect tablets to a Pharmacy medicine". ^ "Viagra to be available without prescription in UK". This section identifies the active ingredient in Viagra® and lists comparable pharmaceutical brands available in Canada. Viagra® is a brand-name medication containing the active ingredient sildenafil. In the Canadian pharmaceutical landscape, it belongs to a class of drugs that manage blood flow through specific enzymatic pathways. Other competing Canadian brands that utilize similar pharmacological mechanisms include Cialis® (tadalafil), Levitra® (vardenafil), and Staxyn® (vardenafil). Another sildenafil-based brand, Revatio®, is also available but is often dispensed in different strengths for distinct clinical purposes.

How does Sildenafil works?

^ Goldstein I, Lue TF, Padma-Nathan H, Rosen RC, Steers WD, Wicker PA (May 1998). "Oral sildenafil in the treatment of erectile dysfunction. Archived from the original on 14 January 2012. "Onset and duration of action of sildenafil for the treatment of erectile dysfunction". ^ "Scientist who developed Viagra receives knighthood in New Year's Honours".

Sexually Transmitted Diseases

Archived from the original on 14 January 2023. "Sildenafil: from angina to erectile dysfunction to pulmonary hypertension and beyond". Archived from the original on 26 September 2008. Our clinicians regularly offer patients the opportunity to take part in trials of new drugs and treatments. Morriston Hospital in Swansea, was the first in the world to trial Viagra! In Canada, this medication is primarily available as oral tablets in three standardized strengths. Viagra® is produced as blue, film-coated, diamond-shaped tablets. The available formats in Canadian pharmacies include: Viagra® works by protecting specific molecules that allow smooth muscles to relax and increase blood flow. At a biological level, sildenafil is a selective inhibitor of the PDE5 enzyme. Under normal conditions, this enzyme breaks down a substance called cyclic guanosine monophosphate (cGMP). By blocking PDE5, Viagra® allows cGMP levels to remain elevated. This leads to the relaxation of smooth muscles in the walls of blood vessels, which facilitates increased blood flow to specific areas of the body. Usage involves oral administration according to strict timing and safety guidelines provided by a healthcare professional. Viagra® is taken orally, generally with or without food. Because its absorption can be delayed by high-fat meals, timing is an essential pharmaceutical consideration. It is typically administered as a single dose when needed, and it is strictly recommended that users do not exceed one dose within a 24-hour period. Dosage adjustments are made based on individual physiological responses and safety profiles. Proper storage ensures the chemical stability and shelf-life of the sildenafil citrate compound. Temperature: Store at room temperature between 15°C and 30°C. Environment: Keep the tablets in a dry place away from moisture (avoid bathroom cabinets). Safety: Ensure the medication is kept in its original packaging and out of reach of children. Users may experience common physiological shifts or rare, more serious reactions requiring immediate clinical attention. Abnormal vision (such as a blue color tinge or blurred vision) Priapism: A prolonged and potentially painful physiological reaction lasting over four hours. Sudden Vision Loss: Rare reports of decreased or loss of vision in one or both eyes. Sudden Hearing Decrease: Sudden decrease or loss of hearing, sometimes accompanied by dizziness. Health Canada emphasizes strict precautions regarding cardiovascular health and specific pre-existing medical conditions. Before using Viagra®, it is vital to have a cardiovascular screening. The medication can cause a temporary decrease in blood pressure. It is not recommended for individuals with severe heart or liver problems, or those who have recently had a stroke or heart attack. Health Canada also warns that anyone with a history of non-arteritic anterior ischemic optic neuropathy (NAION) should exercise extreme caution. Certain substances, particularly those affecting blood pressure or liver enzymes, can cause dangerous interactions. The most critical contraindication for Viagra® is the use of nitrates (often prescribed for chest pain), as the combination can lead to a sudden, life-threatening drop in blood pressure.

Medical Condition	Description	Typical Dosage	Approved Age Range
Erectile Dysfunction	Improves blood flow for erections	50 mg	18+
Pulmonary Arterial Hypertension	Lowers blood pressure in lungs	20 mg, 40 mg	18+
Raynaud's Phenomenon	Treats blood vessel spasms	Under study	18+
Altitude Sickness	Off-label use for high altitude	Off-label	Adults only

Alpha-blockers: May cause low blood pressure when combined. Protease inhibitors: Can significantly increase the levels of sildenafil in the blood. CYP3A4 inhibitors: Certain antibiotics or antifungal medications that affect drug metabolism.