Who Should Take Viagra and How Long Does It Work?

Viagra is a prescription medication for men with erectile dysfunction, containing the active ingredient sildenafil citrate. Understanding who can safely take Viagra and how it works helps ensure effective treatment. At EverydayMeds, we offer both branded Viagra and generic sildenafil following a clinical consultation with our UK-licensed prescribers, giving patients choice between options.

  • Adult men aged 18+ with diagnosed erectile dysfunction
  • Those with no serious heart conditions or recent cardiovascular events
  • Men not taking nitrate medications or riociguat
  • Patients without severe liver impairment or very low blood pressure
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Not sure which one? Here's the honest comparison.

Sildenafil
~60 min
~4 hrs
you like to plan ahead
Explore now
Tadalafil (as-needed)Most prescribed
~30 min
up to 36 hrs
you want a whole weekend covered
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Tadalafil Daily
always active
continuous
you never want to think about timing
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Vardenafil
~15–30 min
~8 hrs
you want the fastest onset
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How ED treatment works in your body.

Increases blood flow

Increases blood flow

When PDE5 is suppressed, blood is able to flow more freely through the body—including to the (you guessed it) penis.

Increase erections

Increase erections

More blood flow to the penis means harder, more satisfying erections once you're sexually stimulated.

Understanding Viagra Eligibility and Effectiveness

Who Is Suitable for Viagra Treatment?

Viagra is specifically designed for adult men aged 18 and over who experience erectile dysfunction. To determine suitability, a comprehensive clinical assessment evaluates your medical history, current medications, and cardiovascular health. This prescription-only medicine requires consultation with a qualified healthcare professional who can assess whether Viagra or generic sildenafil is appropriate for your individual circumstances.

How Long Does Viagra Take to Work?

Viagra typically begins working within 30 to 60 minutes of taking the tablet. The medication works by increasing blood flow to the penis when you become sexually aroused - it does not cause automatic erections. Sexual stimulation is still required for the medication to be effective. The effects can last between 4 to 6 hours, though this doesn't mean an erection will persist for this duration.

Factors Affecting Viagra's Effectiveness

Several factors can influence how quickly Viagra works and its effectiveness. Taking the medication on an empty stomach may help it work faster, as fatty meals can delay absorption. Alcohol consumption should be limited, as it may reduce the medication's effectiveness and increase the risk of side effects. Your age, overall health, and the severity of erectile dysfunction can also impact how well Viagra works for you.

Who Should Not Take Viagra?

Certain individuals should not take Viagra due to safety concerns. Those taking nitrate medications for chest pain or heart conditions face dangerous interactions that can cause severe drops in blood pressure. Men with recent heart attacks, strokes, or severe heart disease require careful evaluation. Severe liver impairment, very low blood pressure, and allergies to sildenafil are also contraindications.

Dosage and Safety Considerations

Viagra is available in 25mg, 50mg, and 100mg strengths, with 50mg being the typical starting dose. Your prescriber may adjust this based on effectiveness and tolerability. Only one dose should be taken within 24 hours. EverydayMeds offers both branded Viagra and generic sildenafil, allowing patients to choose based on preference and budget while maintaining the same active ingredient and effectiveness.

Starting Your Treatment Safely

Beginning Viagra treatment requires proper medical supervision through our online consultation process. Our UK-licensed prescribers review your medical history, current medications, and health status to ensure safe prescribing. Regular monitoring helps optimise treatment effectiveness while maintaining safety. Both Viagra and sildenafil options are available following successful consultation, giving you flexibility in your treatment choice.

What you need to know about erectile dysfunction

It's one of the most common conditions we treat, and one of the most treatable.

What is Erectile Dysfunction?
ED means finding it hard to get or keep an erection firm enough for sex. It's not unusual to have an off night; the point at which it's worth doing something is when it's happening regularly, or when it's starting to bother you.
How will I feel when I take ED medication?
For most men, nothing feels different day to day. The medication works in the background — when you're sexually aroused, it helps blood flow where it's needed, so erections come more easily and last longer. It doesn't cause arousal on its own. Some men notice mild, short-lived effects like a headache, facial flushing or a stuffy nose, which usually pass as the dose wears off.
Why do I need a prescription for ED medication?
ED treatments are prescription-only medicines in the UK because they aren't suitable for everyone — for example, alongside certain heart conditions or medications like nitrates. That's why we ask you to complete a short online consultation first. A UK-registered prescriber reviews your answers to make sure your chosen treatment is safe and right for you before it's dispensed.
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