[62] It soon became
| Condition | Warning Level | Reason |
|---|---|---|
| Uncontrolled hypertension | High | Risk of severe hypotension |
| Cardiovascular disease | High | Increased cardiac risk |
| Use of nitrate medications | High | Dangerous drop in blood pressure |
| Retinitis pigmentosa | Moderate | Potential retinal complications |
a great success: annual
- Viagra's mechanism involves inhibiting the enzyme PDE5.
- The drug requires sexual stimulation to be effective.
- Pfizer's research on sildenafil was crucial for Viagra's development.
- The medication is designed to last for about 4-6 hours.
- Viagra has been linked to minor vision changes such as blue tinting.
- It is essential to follow medical advice when using Viagra.
- Viagra's international approval varied, with some countries restricting its use.
- Pfizer invested heavily in marketing Viagra to physicians and consumers.
- The medication's popularity saw a rise alongside increased awareness of ED.
sales of Viagra peaked
- Sildenafil, in Viagra, also shows promise in treating certain types of Raynaud’s phenomenon.
- Variations of Viagra have been developed for different durations of action.
- Pfizer faced patent battles over Viagra's original formulations.
- The drug is typically well-tolerated, but allergic reactions are possible.
- Viagra's packaging includes detailed instructions for safe use.
- The role of Viagra in managing other health conditions is still under study.
- Pfizer's development of Viagra was a key milestone in sexual medicine.
- The drug has been credited with increasing awareness of sexual health.
- Viagra's impact on male aging and health has been extensively studied.
in 2008 at US$1.934 billion.
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The molecular mechanism of smooth muscle relaxation involves the enzyme CGMP-dependent protein kinase, also known as PKG. This kinase is activated by cGMP and it phosphorylates multiple targets in the smooth muscle cells, namely myosin light chain phosphatase, RhoA, IP3 receptor, phospholipase C, and others. [50] Overall, this results in a decrease in intracellular calcium and desensitizing proteins to the effects of calcium, engendering smooth muscle relaxation. The molecular structure of sildenafil is similar to that of cGMP and acts as a competitive binding agent of PDE5 in the corpus cavernosum, resulting in more cGMP and increased penile response to sexual stimulation. [49][51] Without sexual stimulation, and therefore lack of activation of the NO/cGMP system, sildenafil should not cause an erection.
Drug Interactions
Other drugs that operate by the same mechanism include tadalafil (Cialis) and vardenafil (Levitra). Sildenafil is broken down in the liver by hepatic metabolism using cytochrome p450 enzymes, mainly CYP450 3A4 (major route), but also by CYP2C9 (minor route) hepatic isoenzymes. The major product of metabolisation by these enzymes is N-desmethylated sildenafil, which is metabolised further. This metabolite also has an affinity for the PDE receptors, about 40% of that of sildenafil. Thus, the metabolite is responsible for about 20% of sildenafil's action. In the US, even
| Product | Dosage | Quantity + Bonus | Price | |
|---|---|---|---|---|
| Viagra Oral Jelly | 100mg | 110 + 9 Sachets | 284.63€ 271.08€ | |
| Viagra Generic | 150mg | 30 + 2 Pills | 72.32€ 68.88€ | |
| Viagra Super Active | 100mg | 20 + 4 Pills | 48.05€ 45.76€ | |
| Viagra Professional | 100mg | 90 + 2 Pills | 207.09€ 197.23€ | |
| Viagra Generic | 200mg | 30 + 2 Pills | 83.07€ 79.11€ | |
| Viagra Generic | 150mg | 60 + 4 Pills | 111.25€ 105.95€ | |
| Viagra Professional | 100mg | 270 + 6 Pills | 456.97€ 435.21€ | |
| Viagra Generic | 50mg | 270 + 8 Pills | 198.48€ 189.03€ | |
| Viagra Soft Tabs | 100mg | 270 + 10 Pills | 419.95€ 399.95€ | |
| Viagra Generic | 25mg | 10 Pills | 25.19€ 23.99€ | |
| Viagra Generic | 200mg | 90 + 6 Pills | 170.79€ 162.66€ |
though sildenafil is available only
Non-medical use
Sildenafil is excreted as metabolites predominantly in the feces (about 80% of administered oral dose) and to a lesser extent in the urine (around 13% of the administered oral dose). If taken with a high-fat meal, absorption is reduced; the time taken to reach the maximum plasma concentration increases by around one hour, and the maximum concentration itself is decreased by nearly one-third. When taken orally, sildenafil for erectile dysfunction results in an average time to onset of erections of 27 minutes (ranging from 12 to 70 minutes). Sublingual use of sildenafil for erectile dysfunction results in an average onset of action of 15 minutes and lasting for an average of 40 minutes. The preparation steps for synthesis of sildenafil are:[54] Methylation of 3-propylpyrazole-5-carboxylic acid ethyl ester with hot dimethyl sulfate Hydrolysis with aqueous sodium hydroxide (NaOH) to free acid Carboxamide formation with refluxing thionyl chloride/NH4OH Reduction of nitro group to amino group Sildenafil (compound UK-92,480) was synthesized by a group of pharmaceutical chemists led by Simon Campbell[55] working at Pfizer's Sandwich, Kent, research facility in England.
How does sildenafil work (mechanism of action)?
It was initially studied for use in hypertension (high blood pressure) and angina pectoris (a symptom of ischaemic heart disease). [56] The first clinical trials were conducted in Morriston Hospital in Swansea. [57] Phase I clinical trials under the direction of Ian Osterloh suggested the drug had little effect on angina, but it could induce marked penile erections. [58][59] Pfizer therefore decided to market it for erectile dysfunction, rather than for angina; this decision became an often-cited example of drug repositioning. [60][61] The drug was patented in 1996, approved for use in erectile dysfunction by the FDA on 27 March 1998, becoming the first oral treatment approved to treat erectile dysfunction in the United States, and offered for sale in the United States later that year. by prescription from a
What happens if I overdose?
[4] Other drugs that interfere with the metabolism of sildenafil include erythromycin and cimetidine, both of which can also lead to prolonged plasma half-life levels. The use of sildenafil and an α1 blocker (typically prescribed for hypertension or for urologic conditions, such as benign prostatic hypertrophy) at the same time may lead to low blood pressure, but this effect does not occur if they are taken at least 4 hours apart. Concomitant use of nitric oxide donors, organic nitrites and nitrates,[30] such as: nitroglycerinisosorbide mononitrateisosorbide dinitratesodium nitroprussidealkyl nitrites (commonly known as "poppers") Concomitant use of soluble guanylyl cyclase stimulators, such as riociguat Sildenafil should not be used if sexual activity is inadvisable due to underlying cardiovascular risk factors. Sildenafil's popularity with young adults has increased over the years. [32] Sildenafil's brand name, Viagra, is widely recognized in popular culture, and the drug's association with treating erectile dysfunction has led to its recreational use.
What should I tell my healthcare provider before taking sildenafil?
[33] The reasons behind such use include the belief that the drug increases libido, improves sexual performance,[33] or permanently increases penis size. [34] Studies on the effects of sildenafil when used recreationally are limited, but suggest it has little effect when used by those who do not have erectile dysfunction. In one study, a 25 mg dose was shown to cause no significant change in erectile quality, but did reduce the postejaculatory refractory time. [35] This study also noted a significant placebo effect in the control group. Unprescribed recreational use of sildenafil and other PDE5 inhibitors is noted as particularly high among users of illegal drugs. doctor, it was advertised directly
| Medication | Generic Name | Onset of Action | Duration | Common Dosage | Notes |
|---|---|---|---|---|---|
| Viagra | Sildenafil citrate | 30-60 minutes | 4-6 hours | 50-100 mg | Most widely used ED drug |
| Cialis | Tadalafil | 30-60 minutes | Up to 36 hours | 10-20 mg | Longer-lasting effect |
| Levitra | Vardenafil | 25-60 minutes | 4-5 hours | 10-20 mg | Similar to Viagra, different formulation |
to consumers on TV
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[36] Sildenafil is sometimes used to counteract the effects of other substances, often illicit. [33] Some users mix it with methylenedioxymethamphetamine (MDMA, ecstasy), other stimulants, or opiates in an attempt to compensate for the common side effect of erectile dysfunction, a combination known as "sextasy", "rockin' and rollin'", "hammerheading", or "trail mix". [33] Mixing it with amyl nitrite, another vasodilator, is particularly dangerous and potentially fatal. The 2007 Ig Nobel Prize in aviation went to Patricia V. Agostino, Santiago A.
Is Viagra used long term?
Plano, and Diego A. Golombek of Universidad Nacional de Quilmes, Argentina, for their discovery that sildenafil helps treat jet lag recovery in hamsters. Professional athletes have been documented using sildenafil, believing the opening of their blood vessels will enrich their muscles. In turn, they believe it will enhance their performances. Acetildenafil and other synthetic structural analogs of sildenafil which are PDE5 inhibitors have been found as adulterants in a number of "herbal" aphrodisiac products sold over-the-counter. (famously being endorsed by former
- Pfizer's Viagra revolutionized how sexual dysfunction is viewed and treated.
- The pill became a symbol of modern male health empowerment.
- Many studies explore Viagra's impact on psychological well-being.
- The medication's patent expiration increased competition among generics.
- Pfizer remains a leader in erectile dysfunction medications.
- Viagra's marketing included significant digital and traditional media campaigns.
- The drug has been integrated into broader health and wellness discussions.
- Education on safe use has improved patient outcomes.
- Viagra's development marked a significant milestone in pharmacotherapy for ED.
United States Senator Bob
- Viagra's success led to other Pfizer ED treatments, like Cialis.
- The medication is sometimes combined with other treatments for enhanced effect.
- Pfizer's marketing included advertisements in various media worldwide.
- Viagra has a detailed prescribing information guide for physicians.
- The shelf life of Viagra tablets is usually around 2-3 years.
- Pfizer offers educational resources about erectile dysfunction and treatment options.
- Viagra was among the first drugs to demonstrate the use of PDE5 inhibitors.
- The drug's impact extended beyond medicine into popular culture.
- Pfizer engaged in clinical trials to explore Viagra's long-term safety.
Dole and football star Pelé).
People who purchased Pfizer Viagra 50mg Tablet 2s also bought
[41] These analogs have not undergone any of the rigorous testing that drugs like sildenafil have passed, and thus have unknown side-effect profiles. [42] Some attempts have been made to ban these drugs, but progress has been slow so far, as, even in those jurisdictions that have laws targeting designer drugs, the laws are drafted to ban analogs of illegal drugs of abuse, rather than analogs of prescription medicines. However, at least one court case has resulted in a product being taken off the market. The US Food and Drug Administration (FDA) has banned numerous products claiming to be Eurycoma longifolia that, in fact, contain only analogs of sildenafil. [44][45][46] Sellers of such fake herbals typically respond by just changing the names of their products.
More FAQ
Sildenafil and/or N-desmethylsildenafil, its major active metabolite, may be quantified in plasma, serum, or whole blood to assess pharmacokinetic status in those receiving the drug therapeutically, to confirm the diagnosis in potential poisoning victims, or to assist in the forensic investigation in a case of fatal overdose. Nitric oxide (NO) in the corpus cavernosum of the penis binds to guanylate cyclase receptors, which results in increased levels of cGMP, leading to smooth muscle relaxation (vasodilation) of the intimal cushions of the helicine arteries. This smooth muscle relaxation leads to vasodilation and increased viagra super inflow of blood into the spongy tissue of the penis, causing an erection. [49] Robert F. Furchgott, Ferid Murad, and Louis Ignarro won the Nobel Prize in Physiology or Medicine in 1998 for their independent study of the metabolic pathway of nitric oxide in smooth muscle vasodilation.