Treatment of Erectile Dysfunction With Sildenafil Citrate in Renal Allograft Recipients: A Randomized, Double-Blind, Placebo-Controlled, Crossover Trial

Sildenafil > sildenafil citrates


The dosage may need to be reduced in people with kidney or liver disease.

What to avoid

High levels of PDE-5 are found in the penis, lungs, and retina. PDE-5 is also found throughout the body within the smooth muscle cells of the blood vessels and muscles. Sildenafil belongs to the drug class called phosphodiesterase (PDE) type 5 inhibitors. Sildenafil (Viagra, Vybrique brands and generic) is used to treat erectile dysfunction (ED, impotence). It increases blood flow to the penis following sexual stimulation by blocking the enzyme responsible for the breakdown of cGMP.

Storage Class

This allows men to keep an erection hard enough for sex. Sildenafil (Viagra, Vybrique brands and generic) only works following sexual stimulation. It works within 30 to 60 minutes, but may be taken up to four hours before sexual activity. Sildenafil (Revatio brand) reduces high blood pressure associated with pulmonary arterial hypertension (PAH). This improves the ability to exercise in people with PAH and delays any worsening of their symptoms. More research is needed to establish if sildenafil has a role in sexual dysfunction in women.

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Sildenafil offers no protection against sexually transmitted diseases. Note: In general, seniors or children, people with certain medical conditions (such as liver or kidney problems, heart disease, diabetes, seizures) or people who take other medications are more at risk of developing a wider range of side effects. Sildenafil is used to treat erectile dysfunction (ED) (Viagra, Vybrique brands, generic) and to reduce blood pressure in pulmonary arterial hypertension (PAH) (Revatio brand).

Side Effect Frequency Severity Management Tips
Headache Very common Mild to moderate Analgesics if needed
Flushing Common Mild Cool environment, hydration
Dyspepsia Common Mild Dietary adjustments
Nasal Congestion Less common Mild Decongestants if necessary
Dizziness Less common Mild Avoid sudden movements

It is taken when needed for ED approximately 1 hour before sexual stimulation (maximum dose once daily) and daily for PAH. A headache, stomach upsets, and flushing are the sildenafil premature ejaculation main side effects, and it should not be taken within 24 hours of a nitrate. If you are taking sildenafil (Viagra, Vybrique) for ED, do not take it more than once a day. Take an hour before sexual stimulation (range 30 minutes to 4 hours). If you take it with a high-fat meal it may delay how quickly it starts working. Place sildenafil film on your tongue and allow it to dissolve. If you are taking sildenafil (Revatio) for PAH, take it as directed (the usual dosage is three times daily). You can take it either with or without food.

Utilisation dans l'hypertension artérielle pulmonaire

Viagra is also known as “the little blue pill” because of its blue color, while generic sildenafil tends to be a white color. Disclaimer: Healthline has made every effort to make certain that all information is factually correct, comprehensive, and up to date. However, this article should not be used as a substitute for the knowledge and expertise of a licensed healthcare professional. You should always consult your doctor or other healthcare professional before taking any medication. The drug information contained herein is subject to change and is not intended to cover all possible uses, directions, precautions, warnings, drug interactions, allergic reactions, or adverse effects.

Revatio Injection

The absence of warnings or other information for a given drug does not indicate that the drug or drug combination is safe, effective, or appropriate for all patients or all specific uses. USP Certificates/Product Information Sheets and Valid Use Dates View the USP Certificate or Product Information Sheet in the table above to view additional product details, including available label text and storage information. View the USP Certificate or Product Information Sheet in the table above to view additional product details, including available label text and storage information. 1The Harmonized System (HS) code provided on this webpage is for informational purposes only and is subject to change without notice. The exporter and/or importer of record is responsible for determining the accuracy of items at the time of export/import per U.S. Do not consume grapefruit or grapefruit products while taking sildenafil. Always talk to your doctor before taking ANY medication for ED. Some ED medications are not suitable for men with certain medical conditions, and your doctor can advise you on an alternative. Call your doctor immediately if you experience dizziness or feel nauseous during sexual activity, or develop pain, numbness, or tingling in your chest, arms, neck, or jaw. Do not take sildenafil if you are also taking a nitrate drug (such as nitroglycerin or isosorbide dinitrate/mononitrate) for chest pain or heart problems. Do not take sildenafil with recreational drugs such as "poppers".

Parameter Value Description Notes
Absorption Rapid Peak plasma levels in 30-120 mins After oral administration
Bioavailability 40% Percentage of dose reaching systemic circulation Subject to food effects
Half-life 4 hours Time for plasma concentration to reduce by half ---
Metabolism Liver (CYP3A4 enzymes) Mainly via CYP3A4 and CYP2C9
Excretion Feces and urine 80% via feces, 13% via urine

Taking these substances together can cause a sudden and dangerous drop in blood pressure.

  • Sildenafil citrate’s patent expiration increased market competition.
  • Generics help reduce treatment costs globally.
  • Pharmaceutical companies conduct clinical trials regularly.
  • Safety monitoring continues post-marketing.
  • Adverse event reporting is essential for drug safety.
  • Patients should only use approved formulations.
  • Counterfeit sildenafil products are a concern.
  • Purchase from reputable sources is advised.

Always buy your ED medications from a reputable supplier as there are a lot of counterfeit products on the market. Certain lifestyle and psychological factors, such as smoking, drinking, and stress, can impact ED. Eliminating these - for example, staying more active, losing weight if you are overweight, reducing alcohol intake, stopping smoking, and reducing stress - may also help improve ED. Never take other ED medications at the same time as taking sildenafil. Do not take Viagra while taking Revatio and vice-versa. Seek urgent medical advice if an allergic reaction, sudden vision loss, or painful erections lasting more than four hours occur. Drinking alcohol after taking sildenafil may lower blood pressure and decrease sexual performance. If you are a woman of childbearing age taking sildenafil (brand Revatio) for PAH, then tell your doctor if you become pregnant or are intending to become pregnant.

  • The discovery of sildenafil began with research on heart drugs.
  • It was found to cause vasodilation as a side effect.
  • Pfizer refined the drug for erectile dysfunction.
  • It became a blockbuster drug upon FDA approval.
  • Sildenafil has helped millions worldwide.
  • It has changed perceptions about male sexual health.
  • Ongoing research explores new formulations.
  • Awareness campaigns promote safe usage.

It is not known if sildenafil is distributed into breast milk. Peak plasma concentrations of sildenafil are reached within 30 to 120 minutes of a single dose. Effects of sildenafil, when used for ED, are usually noticeable within 30 to 60 minutes of a single dose.

What special dietary instructions should I follow?

May not be suitable for some people including those with angina, chest pain, other heart conditions, liver or kidney problems, blood or bleeding disorders, stomach ulcers, certain eye conditions, or a physical deformity of the penis (such as Peyronie's disease). Higher dosages of sildenafil are associated with a higher risk of death in children with PAH. For this reason, the FDA does not recommend use in children aged less than 18 years. May interact with some medications including certain antibiotics and antifungals, herbal remedies, HIV medicines, nitrates, and drugs used in the treatment of high blood pressure or prostate disorders. Sildenafil should not be taken with other PDE-5 inhibitors. When used to treat PAH, blood pressure-lowering effects are noticeable within one to two hours. Medicines that interact with sildenafil may either decrease its effect, affect how long it works, increase side effects, or have less of an effect when taken with sildenafil. An interaction between two medications does not always mean that you must stop taking one of the medications; however, sometimes it does. Speak to your doctor about how drug interactions should be managed.

Society and culture

regulations. USP is not responsible for the accuracy or completeness of the information furnished. 2USP procures materials worldwide and most foreign materials do not undergo a fundamental change during the packaging process at USP that would substantially transform the item resulting in a country of origin change from the foreign origin to the United States. Under the Rules of Origin the original foreign country of origin would remain. Animal, Plant, Fish) may require special country importation requirements.USP recommends you contact your country competent authorities to determine if any certifications, permits or licenses may be required prior to ordering.Material Origins are found within the Product under Origin Information.

How it works

Sildenafil is used to treat erectile dysfunction (ED) in men or pulmonary arterial hypertension (PAH) in both men and women, depending on the brand. Viagra and Vybrique are used for ED and Revatio is used for PAH. Sildenafil works by blocking the action of an enzyme called cGMP-specific phosphodiesterase type-5 (PDE-5). This enzyme breaks down cGMP, a substance that induces smooth muscles to relax. Blocking PDE-5 means increased levels of cGMP within the smooth muscles which promotes muscle relaxation and vasodilation (a widening of blood vessels). Sildenafil is metabolized mainly by CYP3A4 and to some extent by CYP2C9.

6. Response and effectiveness

When used to treat PAH, sildenafil is available as tablets (20 mg) for and an IV injection. When used for ED, sildenafil is available as oral tablets of 25 mg, 50 mg, and 100 mg strengths, or an oral film (Vybrique brand) of 25 mg, 50 mg, 75 mg, and 100 mg strengths. If you are between the ages of 18 and 60, take no other medication or have no other medical conditions, side effects you are more likely to experience include: Dyspepsia, flushing, headache, indigestion, muscle or back pain, and visual disturbances are the most common side effects reported. Other side effects include a drop in blood pressure, insomnia, nasal congestion, or a runny nose and nosebleeds. Sudden hearing loss has also been reported.

Missed Dose

Some people taking sildenafil have had bleeding events; however, it has not been established if this is related to sildenafil use. Rarely, may decrease blood flow to the optic nerve causing sudden vision loss. The risk is greater in people aged older than 50, with diabetes, heart disease, high blood pressure, high cholesterol, who smoke, or with certain pre-existing eye problems. Rarely, may cause other side effects or lead to painful erections lasting longer than four hours. See your doctor immediately if this happens. It also weakly inhibits CYP1A2, 2C(, 2C19, 2D^, 2E1, and 3A4. Any drug that is a substrate of one of these enzymes could potentially interact with sildenafil. In addition, taking sildenafil with too much alcohol can lead to orthostatic hypotension, which is a drop in blood pressure when you go from a sitting or lying down position to standing. Symptoms include a headache, dizziness, or fainting when standing.

Condition Reason Notes
Nitrate therapy in patients Severe hypotension Absolute contraindication
Severe hepatic impairment Altered metabolism Use with caution
Retinitis pigmentosa Possible retinal toxicity Consult ophthalmologist
Hypotension (<90/50 mmHg) Risk of exacerbating low BP Monitor blood pressure

Antacids, such as magnesium hydroxide or aluminum hydroxide may also affect the absorption of sildenafil.