Buy Sildenafil Online UK | Generic Viagra 25mg, 50mg & 100mg | QuickMeds

Sildenafil offers an affordable way to access the most popular erectile dysfunction treatment, Viagra, without paying the premium price.

By increasing blood flow to the penis, sildenafil helps men with ED for up to 4 hours, without having to see your GP.

Start your free online consultation and order Sildenafil from a UK-registered pharmacy

Sildenafil tablets are a prescription-only (POM) treatment for erectile dysfunction (ED), shown to be effective for 69% of men, and available to purchase following an online consultation.

All treatments are supplied by our UK-registered pharmacy regulated by the General Pharmaceutical Council (GPhC), and meets MHRA safety standards.

How To Place an Order

To place an order, head to our website, to the erectile dysfunction section. Hit the start consultation button, and fill out the whole form accurately.

The form will ask questions about your symptoms, your general health along with medical history and if you take any other medication. Once complete, you will be able to add sildenafil to your basket and checkout.

Our registered clinicians will review your responses for clinical suitability and safety. Clinicians may also request additional information, by accessing your NHS health record to ensure the treatment is right for you.

Once approved, orders are packaged appropriately and dispatched usually on the same day with delivery options as soon as the next working day.

How much does Sildenafil cost

The cost of sildenafil varies based on the dose and pack size. Prices correct as of May 2026 are detailed below

What is Sildenafil?

Sildenafil is used to treat erectile dysfunction (ED), helping men achieve and maintain an erection suitable for sex. It is the generic version of Viagra, working in the same way and containing the same active ingredient, sildenafil citrate.

As a PDE-5 inhibitor, sildenafil opens blood vessels increasing blood flow into the spongy tissues of the penis, where it is held, leading to an erection.

How Effective is Sildenafil?

A large clinical trial involving over 8,000 men assessed how effective sildenafil really is. The trial found 74% of men taking the 50mg dose reported improved erections. This increased to 82% with the 100mg dose and 62% with the 25mg dose.

When compared to placebo, which improved erections in only 25% of men, it can be seen sildenafil is indeed effective.

Its effectiveness was also assessed in patients with underlying conditions and found the following percentage of patients experienced improved erections.

Sildenafil success rates, coupled with a low discontinuation rate makes it a viable treatment option for eligible patients.

How Sildenafil Works

Sildenafil works by blocking the PDE-5 enzyme, which normally restricts blood flow. By relaxing blood vessels, it allows increased blood flow to certain parts of the body including the penis.This helps to achieve and maintain an erection during sexual arousal.

Whilst effective, the erection does not spontaneously occur. It is important to be sexually stimulated for the treatment to work.

Most men begin to notice effects within 30–60 minutes, with peak effectiveness around 1 hour after taking a dose. For this reason, it's recommended to take your dose approximately 1 hour before anticipated sexual activity.

How to Take Sildenafil

Take Sildenafil exactly as prescribed by your clinician, taking into account the following:

1. Take one tablet whole with water approximately 30–60 minutes before sexual activity.

2. Do not take more than one dose in 24 hours.

3. Sexual stimulation is required for the medication to work.

4. Avoid heavy or high-fat meals before taking, as this may delay effectiveness.

5. Limit alcohol intake, as it may reduce effectiveness and increase side effects.

Sildenafil dose

The starting dose for most healthy adults is 50mg. This is usually sufficient to achieve a satisfactory erection with minimal side effects.

The lower, 25mg dose is useful for those who are worried about side effects, have liver or kidney problems, or are taking interacting medication which may cause a sudden drop in blood pressure.

The higher, 100mg dose is reserved for patients who did not achieve satisfactory results with the 50mg dose. Additionally, patients with underlying conditions, such as diabetes find the 100mg dose is more effective for them.

Importantly, 100mg is the maximum daily dose and should not be exceeded. Doses higher than 100mg does not make the treatment more effective but significantly increases the risk of side effects.

Who Can Take Sildenafil?

Sildenafil is suitable for adult men who:

• Have difficulty achieving or maintaining an erection,

• Experience reduced erectile firmness,

• Have occasional or ongoing erectile dysfunction.

Sildenafil suits individuals who have planned sexual activity a few times a week. Those who are having sex more often, or have a more spontaneous sex life, may benefit from Tadalafil, a similar medication.

Who Should Not Take Sildenafil?

Whilst a generally safe treatment Sildenafil may not be suitable for everyone.

Do not take Sildenafil if you:

• Are allergic to any of the ingredients listed in the packaging

• Take nitrate medicines for chest pain/angina

• Use poppers (amyl nitrate)

• Use riociguat for pulmonary hypertension

• Are taking other PDE-5 inhibitors

• Have been advised to avoid sexual activity due to heart conditions

• Have a specific eye condition called non-arteritic anterior ischaemic optic neuropathy (NAION)

• Have low blood pressure

• Have had a recent heart attack or stroke

• Have severe liver problems

• Have a rare inherited eye disease (retinitis pigmentosa)

Drug Interactions

Sildenafil can interact with certain medications and are broadly classified into those which either increase sildenafil levels in the body (increasing side effects) or cause a dangerous drop in blood pressure.

Dangerous blood pressure drops

The most serious interactions associated with sildenafil are those that lead to dangerous drops in blood pressure. For this reason, it must not be taken alongside:

• Nitrates - such as glyceryl trinitrate or isosorbide mononitrate.

• Nitric oxide donors - such as poppers (amyl nitrate), a recreational drug

• Guanylate Cyclase Stimulators - such as Riociguat

Increased risk of side effects

Sildenafil is broken down in the body by certain enzymes (CYP3A4 and CYP2C9). Any other drug which is also broken down by the same enzymes, or affects blood flow, can interact with sildenafil and include:

• HIV drugs, such as Ritonavir

• Antifungal medicines - ketoconazole, itraconazole

• Antibiotics, such as erythromycin and clarithromycin, rifampicin

• Anticonvulsants - such as phenytoin, carbamazepine and phenobarbital

• St John's Wort - a herbal therapy used for depression.

Alpha-blockers, used to treat high blood pressure or an enlarged prostate (tamsulosin, doxazosin) can also cause an interaction. Taking them together may lead to orthostatic hypotension, (dizziness or fainting when standing up). These patients are generally advised to start treatment no higher than 25mg.

Other interactions include Grapefruit juice, which can increase sildenafil levels in blood, leading to side effects.

Whilst alcohol is not contraindicated, it can numb the nervous system, affecting natural ability to achieve an erection. Consuming excess alcohol can make it feel like sildenafil isn't working.

Additionally, both alcohol and sildenafil can widen blood vessels. When taken together, they can cause low blood pressure, leading to dizziness, lightheadedness, headaches or fainting.

Side effects

Most common

The most common side effects affecting 1 in 10 people include:

• Headaches

• Dizziness

• Hot flushes

• Nasal congestion

• Nausea

Uncommon

Less common side effects can affect between 1 in 100 and 1 in 1,000 people include:

• Vision changes

• Eye pain

• Light sensitivity

• Bloodshot eyes

• Tinnitus (ringing in the ears)

• Palpitations

• Blood pressure fluctuations

• Nosebleeds

• Upper abdominal pain

• Vomiting

• Reflux

• Muscle aches/pain

• Skin rashes

The patient information leaflet, included with the treatment includes a comprehensive list of side effects.

Rare/serious Side Effects

Serious side effects are rare, affecting 1 in 1,000 to 10,000 people and include:

• Priapism - a prolonged, painful erection lasting longer than 4 hours

• NAION (sudden vision loss)

• Cardiovascular events - such as sudden chest pain, irregular heartbeat, or heart attack/stroke

• Sudden hearing loss - accompanied by tinnitus (ringing) or vertigo

• Anaphylaxis - severe allergic reaction. Symptoms include sudden wheeziness, difficulty breathing, swelling of the eyes, face, lips or throat.

• Severe Skin Reactions - such as Stevens-Johnson syndrome or toxic epidermal necrolysis

If you experience any of these side effects, you should seek immediate medical attention, by calling 999 or going to the nearest A&E immediately.

Sildenafil vs Viagra vs Tadalafil vs Cialis

Whilst an effective treatment for erectile dysfunction, Sildenafil is not the only option. Common alternatives include:

Viagra

Viagra is probably the most well-known ED medication. It contains the same active ingredient as Sildenafil, works in the exact same way and is clinically identical in effectiveness and safety.

Although more expensive, some men prefer to choose Viagra as they are familiar with the brand.

Cialis

Cialis is another branded medication. This treatment contains a different drug, Tadalafil, and may take slightly less time to work than Viagra or sildenafil.

Tadalafil

The generic form of Cialis, Tadalafil, is often more affordable. As it lasts in the body for a much longer dose, it is a good option for those who are having sex often or with a more spontaneous sex life.

It is also available as a low-dose daily pill, to work continuously in the background for spontaneous activity throughout the day.

Click here for more information on both sildenafil and tadalafil to work out which treatment is right for you.