Sildenafil (generic Viagra) tablets to treat erectile dysfunction (25mg, 50mg, 100mg strengths).

  • Low cost alternative to Viagra
  • From £1.35 per tablet
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5 stars 11,800 Dr Fox reviews

How to buy online

  1. Read medical information about erectile dysfunction
  2. Answer medical questions to check for eligibility
  3. Reviewed by doctors - posted from UK pharmacy

Generic Viagra

Sildenafil is the medical or generic name for Viagra. Medically they are the same. Sildenafil is sometimes called generic Viagra. Sildenafil was first marketed under the name Viagra in 1998. In June 2013, when the patent of Viagra expired in the UK and other European countries, prices came down significantly.

Generic sildenafil is available at much lower cost, from £1.35 per tablet, while Pfizer branded Viagra costs over £5 per tablet.


Prices of sildenafil tablets
Tablet type4 tablets8 tablets16 tablets32 tablets
Sildenafil 25mg£8.60£14.80£24.80£43.20
Sildenafil 50mg£9.20£16.20£26.80£52.00
Sildenafil 100mg£9.80£17.80£28.40£54.00
Viagra 25mg£24.20£44.30£82.00n/a
Viagra 50mg£29.40£59.50£112.60n/a
Viagra 100mg£33.80£64.45£124.50n/a

Prescription issued online - small prescription fee per order.

Compare prices: Dr Fox prices are 25%-50% lower cost than other online clinics.

Prescription fees

Dr Fox supplies medicine on prescription and charges a small prescription fee based on the order value of each prescription.

Prescriptions are issued by our doctors online and sent electronically to our pharmacy.

If you have your own private paper prescription please post to our pharmacy (details).

Dr Fox prices are 25%–50% lower than other UK online clinics.

Order valuePrescription fee
up to £10£1.00
up to £20£2.00
up to £50£4.00
up to £100£5.00
over £100£8.00
Prices of Sildenafil tablets from UK online clinics (11 July 2017) - qualifying notes
*Dr Fox adds a small prescription fee not included in table above.
  1. The prices shown are listed by the online clinics named after a customer first enters consultation information and is offered prescriptions. It is possible these clinics may have special offers or lower prices for repeat supplies.
  2. Prices may change and are, to the best of our knowledge, accurate on the date stated. All products in stock and new condition.
  3. Dr Fox does NOT claim to provide a superior service to any of the online clinics listed. All the clinics listed, as far as we can tell, comply with all regulation and, as far as we can tell, operate to high ethical standards.
  4. Dr Fox adds a small prescription fee not included in the table (between £1 and £10 depending on value of the order).
  5. To amend the information in this table please contact us
  6. The prices listed in the table do not identify the cost of prescription medicine as online clinics charge a single fee to cover services which includes advice, consultations, prescriptions and dispensing and supply of treatments.
MedicationDr Fox*SuperdrugExpress PharmacyHealth ExpressPharmacy2UMed ExpressLloyds
Sildenafil 25mg x 4£8.60£18.00£19.99£24.99£15.00£15.99£16.00
Sildenafil 25mg x 8£14.80£27.00£29.99£30.00£23.00£29.99£24.00
Sildenafil 25mg x 16£24.80n/a£49.99£60.00£40.00£49.99£45.00
Sildenafil 25mg x 32£43.20n/an/a£89.99£60.00£89.99n/a
Sildenafil 50mg x 4£9.20£24.00£19.99£26.99£23.00£19.99£23.00
Sildenafil 50mg x 8£16.20£40.00£29.99£35.00£38.00£29.99£38.00
Sildenafil 50mg x 16£26.80£68.00£49.99£65.00£60.00£49.99£60.00
Sildenafil 50mg x 32£52.00n/an/a£94.99£86.00£89.99n/a
Sildenafil 100mg x 4£9.80£32.00£19.99£34.99£27.00£19.99£27.00
Sildenafil 100mg x 8£17.80£48.00£29.99£44.99£56.00£29.99£45.00
Sildenafil 100mg x 16£28.40£76.00£49.99£69.99£75.00£49.99£75.00
Sildenafil 100mg x 32£54.00n/an/a£99.99£130.00£89.99n/a
UK delivery£2.90included£2.95included£3.45£2.90included

Delivery charges

UK delivery only: £2.90 per consultation via Royal Mail 24 Signed For (1-3 working days with tracking).

Parcel forwarding services are not permitted. Use only UK home or work delivery address.

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About Sildenafil

Manufacturers and brands of sildenafil

sildenafil drug manufacturer brand logos

Different pharmacy companies produce their own sildenafil tablets. Dr Fox supplies only UK licensed tablets supplied from UK registered pharmacies. The following pharmaceutical companies produce sildenafil: Bristol Labs, Mylan, Teva, Accord, Actavis, Sandoz, Dr Reddys, Zentiva, Pfizer. See brands of sildenafil for more information.

Dr Fox usually supplies the same brand each time, although this may not always be possible. From time to time manufacturers may have stock shortages, and brand switching is then unavoidable. Most men find no difference between brands.

How does sildenafil work?

During sexual arousal blood flow in the penis changes. It is this change in blood flow which produces erections. Sildenafil is known medically as a PDE5 inhibitor. PDE5 inhibitors alter the levels of the natural chemical messengers involved in producing erections.

Why choose sildenafil?

Sildenafil is a tried and tested medicine. Most men find it effective and are not usually troubled by significant side effects. It usually starts to work within 30 minutes of taking a tablet, and usually remains active for about 4 hours. Erections will only occur during this time if there is stimulation. If there is no arousal, there will be no erection. After 4 hours the effects of the tablet wear off.

Alternative tablets include Cialis, Levitra and Spedra. They work in the same way, but for different lengths of time. See tablet differences for further details.

How to take sildenafil

The normal starting dose, in men who have not taken sildenafil before, is one 50mg tablet. Subsequent doses can be adjusted up to a maximum of 100mg as a single dose, or down to 25mg, depending on response. Most men find 50mg sufficient. Sildenafil should not be taken more than once in 24 hours.

The effects of treatment may not be exactly the same each time. It is best to take the same dose that worked previously, increasing the dose only if on several occasions treatment is not successful.

Sildenafil dosage

Sildenafil 25mg tablets

Sildenafil 25mg

Reduced dose recommended when 50mg starting dose is highly effective.

Sildenafil 50mg tablets

Sildenafil 50mg

Starting dose usually recommended for most men taking sildenafil for the first time.

Sildenafil 100mg tablets

Sildenafil 100mg

High strength dose for when 50mg is insufficient, or erection lasts less than 4 hours.

Contraindications and interactions

All men with erectile dysfunction should consult a doctor face-to-face before buying sildenafil tablets online. Sildenafil is not suitable for all men, particularly men who have severe heart disease or a history of stroke. Some prescribed medicines interact with sildenafil, most notably medicines called nitrates, used to treat angina and heart disease.

Checks on the suitability of treatment are carried out during our online consultations. Men who are not eligible to order from Dr Fox should consult with their doctors.

Men should not take Sildenafil without further assessment from their GP when the following apply:

  • Low or high blood pressure
  • Allergies or reactions to past ED treatments
  • Recent heart attack (within 6 weeks) or suffer from angina (heart pain on exertion) or any form of heart disease
  • History of strokes or mini-strokes (transient ischaemic attack)
  • History of vision problems caused by circulation problems
  • History in the family of rare degenerative eye disease
  • Serious kidney (renal) or liver disease
  • Peyronie's disease – angulation or deformity of the penis
  • Leukaemia, multiple myeloma or sickle cell disease
  • Bleeding disorders (such as haemophilia)
  • Current active stomach ulcers (peptic ulcer or gastric ulcer)

Side effects of sildenafil

Most men find sildenafil effective and do not experience significant side effects.

The commonest side effects, affecting up to 1 in 10 men are, nausea, facial flushing, hot flush (symptoms include a sudden feeling of heat in the upper body), indigestion, colour tinge to vision, blurred vision, visual disturbance, stuffy nose and dizziness.

A complete list of side effects can be found in the manufacturer's patient information leaflet.

Allergic type reactions, chest pains or fits, all of which are very rare, require immediate medical attention. Prolonged (4 hours or more) painful erections, a medical condition called priapism, can occur and requires immediate medical attention.

For more information see side effects of Viagra/sildenafil.

What causes erectile dysfunction (ED)?

There is no single factor which causes ED. There are many different causes. The most frequent cause is impaired circulation, which comes in part with ageing. Factors which impair circulation include smoking, lack of exercise, and obesity. Some medical conditions, most notably diabetes, are associated with ED. ED can also occur as a side effect of some prescribed medicines. Operations and trauma, which damages the nerves or blood supply to the penis, can result in ED. This is by no means a complete list.

Alternative ED treatments

Sildenafil tablets support and help natural erections. If ED is caused by severely restricted circulation or damage to the nervous system, tablets may not help.

There are alternative non-tablet treatments, including Vitaros cream, and various other locally applied treatments. Some men benefit from counselling, particularly if stress and performance anxiety are present. A GP should be able to advise.

Drug misuse

Most men take sildenafil to support their usual sexual activity, with resulting benefits to their relationships. Men often find their lives transformed.

If sildenafil is taken in combination with recreational drugs, particularly cocaine, there is an increased risk of adverse effects, particularly prolonged painful erections, which can lead to permanent damage to the penis (priapism).

Sildenafil is not available legally in the UK without a doctor's prescription, except from some specialist pharmacies. Our doctors issue electronic prescriptions, which are sent direct to our UK pharmacy for dispensing and posting.

Patient leaflet

The 'Patient Information Leaflet' supplied with the medication must be read before taking tablets.

Sildenafil patient leaflet

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Sildenafil FAQs

Why must I see a doctor before starting sildenafil?

ED increases with age affecting up to 40% of fifty year olds and it is also common in younger men. In some cases ED is associated with high blood pressure or cholesterol, poor circulation, obesity, lack of exercise, smoking and diabetes, and these are also risk factors for heart disease and stroke. Men with ED need to be examined and tested before starting treatment. It is fine to obtain repeat supplies of sildenafil online, but this does not replace a face-to-face visit to a doctor.

What is the difference between sildenafil and Viagra?

Medically they are the same. Viagra is Pfizer's brand name for sildenafil. Sildenafil is the medical name for the active ingredient in both. Sildenafil and Viagra both come in packs of 4 and 8 tablets in strengths of 25mg, 50mg, and 100mg. They are interchangeable.

Is Viagra stronger than sildenafil?

No, they are medically identical. They are equally effective and have the same side effects and other features.

What is the difference between sildenafil and Levitra and Cialis?

All three are from the same class of medicine (PDE5 inhibitors) and work in the same way. They are all equally effective, but have different durations of action. Sildenafil stays active for about 4 hours, Levitra for 12 hours and Cialis for 36 hours. Sildenafil is most suitable for men intending to be sexually active within a few hours of taking a tablet, after which time the effects will wear off. Unlike sildenafil, Cialis and Levitra are still under patent and hence there are no legally available generic versions of Cialis and Levitra.

Why is sildenafil cheaper than Viagra?

Sildenafil is relatively cheap to produce and is supplied by a number of competing drug companies. This lowers prices. Viagra, which is simply Pfizer's brand of sildenafil, is supplied by Pfizer alone. Pfizer have chosen to keep the price of Viagra higher and can still find a market as some men are loyal to the Viagra brand.

Why are there so many different brands of sildenafil?

Sildenafil is a medicine for which the patent has expired. This means the pharmaceutical company which developed it, Pfizer, cannot prevent other companies producing it. There is a big demand, and about a dozen pharmaceutical companies produce and market their own sildenafil. The following are UK licensed brands: Sandoz, Mylan, Accord, Actavis, Ajanta, Pfizer, Teva, Torrent, Dr Reddys, Bristol Labs, Zentiva. Only buy from registered pharmacies to guarantee tablets meet standards.

Which is the best brand of sildenafil?

If you obtain sildenafil from UK regulated websites and pharmacies there will be no difference. The active ingredient in one 25mg tablet of any brand of UK licensed sildenafil will be the same as any other. The appearance, shape, and colour may vary, but the active ingredient will be the same. Men often have a preference for one brand over another, but usually find that when their preferred brand is not available, they are just as happy with the alternative. See brands of sildenafil page.

Why, for many years, was Viagra the only type of sildenafil tablet available?

The drug company Pfizer developed and patented sildenafil and marketed it under the name Viagra. Before the patent ran out only Pfizer was permitted to make sildenafil. When Pfizer's patent expired 21 June 2013 other drug companies started to make and market sildenafil tablets using the name 'sildenafil'.

Why does the price of sildenafil vary between pharmacies?

Pharmacies buy medicines on the wholesale market, paying quite low amounts for sildenafil, which is made by various drug companies. Pharmacies then set their own mark-up when selling tablets on to patients. Dr Fox keeps its prices low and benefits from high levels of repeat ordering. Other pharmacies take a different approach. It is worth shopping around.

Can I buy sildenafil without a prescription?

Yes. Since April 2018 pharmacies can supply Viagra Connect (sildenafil 50mg) without a prescription, although this is significantly more expensive. Viagra and generic sildenafil remain a prescription only medicine which can be dispensed legally only from registered pharmacies. UK online pharmacies use electronic prescriptions issued by doctors or specialist pharmacists. When you order medicine from Dr Fox a prescription is issued electronically to our licensed pharmacy, so you do not need a paper prescription from your own doctor. Use only registered pharmacies, as unregulated suppliers are not subject to controls and will be selling fake medicine which may be ineffective and possibly dangerous.

Can I get sildenafil on the NHS?

Yes, GPs can prescribe sildenafil, but usually do so in only limited amounts in line with strict eligibility criteria. NHS prescription fees will apply. In some cases it will cost less to buy sildenafil online than obtaining it repeatedly through the NHS where the prescription fees may be higher. See Sildenafil on the NHS page.

Can sildenafil tablets be divided?

Some brands of sildenafil tablets are scored to enable them to be cut in two. Torrent tablets usually supplied by Dr Fox are scored and can be split. Other brands are un-scored and can be difficult to split without shattering.

Can I drink with sildenafil?

It is best not to drink when taking sildenafil or to drink only a small amount (one or two units). Alcohol is a depressant and tends to reduce erections and will reduce the effectiveness of treatment. Some side effects of sildenafil are likely to increase with alcohol, particularly low blood pressure.

What should I do if sildenafil does not work or stops working?

Sildenafil is usually effective and usually remains effective at the same dose over many years. The body does not get used to sildenafil or become immune to its effects. If there is a poor response from time to time, this is to be expected, as the circumstance around taking the tablets may not be right every time. If this happens, you should try again with the same strength tablets and can expect the same good responses as you had previously. If your usual sildenafil repeatedly fails to help, you should consult your regular doctor to see if there has been a change in the underlying cause of your ED or to see if another type of treatment might be more suitable. See My ED medicine is not working page.

Can I take sildenafil and Levitra and Cialis at the same time?

No, the combination of ED tablets is potentially dangerous and can cause toxic effects of overdose. If one type of tablet does not work, its strength can be increased or an alternative type of tablet can be tried, but treatments must not be combined. Leave at least 24 hours between sildenafil and Levitra and other treatments, and 48 hours after Cialis.

Can I take sildenafil with other prescription medicines?

Sildenafil can be taken with most other prescription medicines, with some notable exceptions. Nitrates used mainly to treat heart disease and angina can interact and cause a dangerous fall in blood pressure. For a full list of interacting medicines check the patient information leaflet supplied with the tablets. Checks for interactions are carried out in online consolations.

See also erectile dysfunction FAQs page.

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Authored 24 October 2015
by Dr Tony Steele

Reviewed 30 July 2017 by Dr B. Babor, Dr A. Wood, Dr P. Hunt

Last updated 16 May 2018

Product reviews

Sildenafil rated 4.55/5 in 2669 product reviews

See over 11,800 service reviews of Dr Fox

Sildenafil 100mg

Excellent product. Helps provide an erection and maintains it for several hourse when stimulated..

13/08/2018 18:04
Anonymous Verified

Sildenafil 100mg

Generally very effective.... Great results..... Not so much with last batch

13/08/2018 12:33
Anonymous Verified

Sildenafil 50mg

Works well with no side effects

13/08/2018 11:45
Anonymous Verified

Sildenafil 50mg

A good product, in my case a smaller dose would be better.

13/08/2018 10:52
Anonymous Verified

Sildenafil 100mg

Effective lasted about 45mins

12/08/2018 22:38
Anonymous Verified

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