• Results in 30-60 minutes
  • Helps to maintain an erection
  • Price as low as 70p per tablet
  • Cost effective alternative to the iconic 'blue pill'

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Overview

Experiencing difficulties with erections can feel frustrating and impact both confidence and relationships — but you are not alone. Erectile dysfunction (ED) is extremely common, and safe, effective treatments are available. Sildenafil is one of the most widely used and trusted options, offering a reliable way to restore sexual performance and reassurance when you need it most.

Sildenafil belongs to a group of medicines called PDE5 inhibitors, which work by increasing blood flow to the penis. When taken before intimacy, it helps support firmer, longer-lasting erections in response to sexual stimulation. This means it doesn’t cause automatic erections — instead, it gives your body the boost it needs to perform naturally.

Known for being affordable, effective, and well-studied, Sildenafil is often the first choice for men seeking ED treatment. Millions worldwide have used it with success, and it remains a go-to option for restoring confidence in the bedroom.

At SwiftMedi, every order is carefully reviewed by a UK-registered prescriber, ensuring treatment is safe and suitable for you. Medication is delivered quickly and discreetly to your door — helping you regain control without unnecessary embarrassment.

 

What is Sildenafil?

 Sildenafil is best known as the active ingredient in Viagra, but it is also available as a generic medicine. It is licensed in the UK for treating erectile dysfunction and, under the brand name Revatio, for pulmonary arterial hypertension. When you take a sildenafil tablet, it works by blocking the enzyme PDE‑5, which relaxes the blood vessels and allows more blood to flow into specific areas. For men with Erectile Dysfunction (ED), this improved blood flow helps achieve a firm erection when sexually aroused. In pulmonary hypertension, it relaxes the vessels in the lungs, reducing strain on the heart.

Sildenafil tablets are available in strengths from 25 mg to 100 mg. The typical starting dose for ED is 50 mg, taken as needed. Healthcare professionals may adjust the dose to 25 mg or 100 mg depending on how well it works and whether you experience side effects. Importantly, you should never take more than one dose in 24 hours, and you must be sexually stimulated for it to work. Sildenafil is not an aphrodisiac and will not increase desire on its own.

ED is common, affecting over half of men aged 40 to 70, and can be caused by health or lifestyle factors such as obesity, high blood pressure, smoking, alcohol consumption, and stress, as well as certain medications. Sildenafil provides a reliable and discreet solution to help improve sexual performance and confidence.

Directions

Following the advice of your prescriber will help ensure sildenafil is safe and effective. Key points to remember include:

  • When to take it: Swallow a tablet whole with water between 30 minutes and 4 hours before sexual activity. Many men find it works best on an empty stomach. A heavy or high‑fat meal can delay its onset.

 

  • Dose guidance: The usual dose is 50 mg, but your prescriber may recommend 25 mg if you are older, have liver or kidney problems, or are taking certain other medicines. Do not exceed 100 mg and never take more than one tablet per day.

 

  • Method: Do not crush or chew the tablet. Take it with a full glass of water. Avoid grapefruit juice, as it can increase the level of sildenafil in your blood and lead to side effects.

 

  • Missed or extra doses: Sildenafil for erectile dysfunction is taken only when needed. If you are using sildenafil for pulmonary hypertension and miss a dose, take it as soon as you remember unless it is nearly time for your next dose. Do not double up. If you accidentally take too much, contact a healthcare professional straight away.

 

  • Onset and duration: It usually takes 30 to 60 minutes to start working. The effects last for around 4 hours, though this can vary.

Side Effects

Sildenafil is generally well tolerated, but some men may experience side effects, including:

  • Dizziness
  • Hot flushes
  • Headaches
  • Nausea
  • Indigestion
  • Stuffy nose


Avoid grapefruit and grapefruit juice while taking sildenafil, as these can interfere with its metabolism, increasing side effects or reducing effectiveness.


Safety Information and Precautions
Sildenafil is not suitable for everyone. Avoid taking it if you:

  • Have low blood pressure or certain blood disorders
  • Take nitrate medications for chest pain (angina)
  • Have severe heart or liver problems
  • Have had a recent stroke or heart attack
  • Have penile deformities such as Peyronie’s disease


Always disclose your full medical history to a healthcare professional before starting sildenafil. It may interact dangerously with some medications, especially nitrates and alpha-blockers.

Seek immediate medical help if you experience:

  • Chest pain or allergic reactions (swelling, breathing difficulties)
  • Vision loss or severe vision changes
  • Painful or prolonged erections lasting over two hours

Warnings

Sildenafil is not suitable for everyone. Always discuss your medical history and current medications with a prescriber before starting treatment.

  • Medical conditions: Tell your prescriber if you have heart or blood vessel disease, low or high blood pressure, liver or kidney problems, vision disorders (such as retinitis pigmentosa), bleeding disorders, stomach ulcers, Peyronie’s disease, sickle cell anaemia, or if you’ve recently had a stroke or heart attack. Sexual activity can put extra strain on the heart, so seek advice if you have cardiac risk factors.

 

  • Pregnancy and breastfeeding: Sildenafil is not usually prescribed for women. If you are pregnant or breastfeeding and have been offered sildenafil for pulmonary hypertension, discuss the potential risks and benefits with your specialist.

 

  • Alcohol: Moderate alcohol consumption is unlikely to interact significantly, but heavy drinking may exacerbate side effects and hinder performance.

 

  • Medicines and interactions: Avoid taking sildenafil with nitrates (such as glyceryl trinitrate), nitric oxide donors (including recreational “poppers”), guanylate cyclase stimulators (e.g. riociguat), some antifungals or antibiotics, HIV protease inhibitors, alpha‑blockers, or other PDE‑5 inhibitors like tadalafil or vardenafil. Combining sildenafil with these medicines can cause dangerous drops in blood pressure. Always check with your prescriber before starting or stopping any medication.

 

  • Grapefruit: Grapefruit or grapefruit juice can raise sildenafil levels in the body and increase the risk of side effects. It’s best to avoid it while taking sildenafil.

 

  • Driving and machinery: If you feel dizzy or notice vision changes after taking sildenafil, wait until these symptoms pass before driving or operating machinery.
Frequently asked questions

  • What is sildenafil and how does it work?

    Sildenafil helps treat erection difficulties by increasing blood flow to the penis during sexual stimulation. It works by relaxing blood vessels, making it easier to get and maintain an erection when you are aroused. This effect is strongest when ED is caused by reduced blood flow, and most men respond well when the dose and timing are correct.

  • How long before sex should I take sildenafil, and how long does it last?

    Sildenafil is usually taken 30–60 minutes before sex, and you still need to be sexually aroused for it to work. For most men, its effects last around four to five hours, although this varies depending on dose, meals, alcohol intake, and overall health. Planning ahead helps ensure you take it at the right time for the best effect. 

  • How effective is sildenafil for erectile dysfunction?

    Sildenafil works for about seven in ten men, especially when ED is linked to reduced blood flow rather than psychological causes. Using the right dose, taking it on time, and avoiding heavy meals can all improve results. If it isn’t effective, a prescriber may adjust the dose or suggest another ED treatment that better matches your symptoms and health.

  • What are the common side effects of Sildenafil?

    The most common side effects include headache, flushing, indigestion, and a blocked nose, which are usually mild and short-lived. Some men notice dizziness or temporary changes in vision. Rarely, serious effects like chest pain or a prolonged erection lasting more than four hours can occur and need urgent medical attention. A prescriber will help check sildenafil is safe for you.

  • Who should not take sildenafil?

    Sildenafil is not suitable if you take nitrate medicines, have very low blood pressure, severe heart or liver problems, or have recently had a heart attack or stroke. It’s also unsuitable for men with certain eye conditions. A prescriber will assess your medical history,  medicines, and symptoms to confirm whether sildenafil is safe and appropriate for you.

  • Do I need a prescription for sildenafil in the UK?

    Most strengths of sildenafil require a prescription, but sildenafil 50 mg (Viagra Connect) can be supplied by a pharmacist after a short consultation. Higher or lower doses need a clinician to review your health and symptoms. This helps ensure you get the safest and most effective option for your type of erection difficulty.

  • What’s the difference between sildenafil and Viagra?

    Viagra is simply the original brand name for sildenafil, and both contain the same active ingredient at the same strengths. They work in the same way and have similar side effects. Many men choose generic sildenafil because it offers the same clinical effect at a lower price while being held to identical safety and quality standards.

  • Does sildenafil work better on an empty stomach?

    Sildenafil works reliably for many men, but a heavy or high-fat meal can delay how quickly it starts working. Taking it on an empty stomach or after a lighter meal usually helps it act faster and feel more effective. This is one of the most common reasons men think sildenafil “isn’t working” when the dose is actually correct.

  • What dose of sildenafil should I start with?

    Many men start with the 50 mg dose, as it provides a good balance of effectiveness and tolerability. Some men may need 25 mg if they have side-effect concerns, while others may require 100 mg for a stronger effect. A prescriber will help choose the safest dose based on your symptoms, health conditions, and medication history.

  • Why does sildenafil sometimes stop working?

    Sildenafil can feel less effective if taken incorrectly, after a heavy meal, or during periods of stress, tiredness, or anxiety. Health changes such as diabetes, blood pressure issues, or new medicines can also affect its performance. A prescriber can review your dose, timing, and symptoms to help improve results or suggest another ED treatment.

  • Can sildenafil affect vision?

    Some men notice temporary visual changes such as a blue tint, blurred vision, or increased sensitivity to light. These effects usually settle as the medicine wears off. Very rarely, serious eye problems have been reported. If you have eye conditions or experience sudden vision changes, you should seek medical advice urgently.

  • How long does sildenafil stay in your system?

    Sildenafil starts to wear off after about four to five hours, but small amounts can remain in the body for up to 24 hours. This doesn’t mean you’ll continue to have effects the whole time. Understanding how long it stays in your system helps guide safe dosing and avoid taking another tablet too soon.

  • Does sildenafil work the first time you take it?

    Some men respond well on the first dose, but others may need to try sildenafil several times before seeing consistent results. Taking it correctly, avoiding heavy meals, and ensuring you feel relaxed and aroused all help it work more reliably. If it doesn’t work after a few attempts, a prescriber may review your dose or consider alternatives.

  • Can sildenafil be used long term?

    Yes. Sildenafil is considered safe for long-term use when monitored by a clinician, and many men use it regularly for years without problems. Regular reviews help ensure the dose remains right for you and check for any new health issues or medication interactions that may affect safety or effectiveness.

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