Buy sildenafil tablets (generic Viagra) from a trusted UK pharmacy

Sildenafil has the same active ingredient as Viagra but costs a lot less. It treats erectile dysfunction and works for the vast majority of men. Your order will be posted in plain & discreet packaging.

Our prices

Strength Quantity Price Stock
25mg4 tablets£7.00In Stock
25mg8 tablets£13.00In Stock
25mg12 tablets£20.00In Stock
25mg16 tablets£25.00In Stock
25mg24 tablets£36.00In Stock
25mg28 tablets£40.00In Stock
25mg32 tablets£45.00In Stock
25mg64 tablets£60.00In Stock
50mg4 tablets£8.45In Stock
50mg8 tablets£15.45In Stock
50mg12 tablets£21.00In Stock
50mg16 tablets£26.05In Stock
50mg24 tablet£38.99In Stock
50mg28 tablets£45.00In Stock
50mg32 tablets£47.99In Stock
50mg64 tablets£64.94In Stock
100mg4 tablets£9.05In Stock
100mg8 tablets£17.05In Stock
100mg12 tablets£24.00In Stock
100mg16 tablets£27.65In Stock
100mg28 tablets£45.00In Stock
100mg24 tablets£39.99In Stock
100mg32 tablets£49.95In Stock
100mg64 tablets£91.99In Stock
Prices exclude a prescription fee. This treatment requires a quick online consultation,
which a doctor will review to determine if a prescription is appropriate.

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Dr Samantha Miller

Reviewed by Dr Samantha Miller MB ChB
(2017, University of Glasgow)
GMC number: 7561464

Information last reviewed 23/05/2021


What is sildenafil?

Sildenafil, brand name Viagra, is a treatment for erectile dysfunction (ED). It works in combination with sexual stimulation to help a man achieve and maintain an erection for long enough to engage in sexual activity.

How does sildenafil work?

Sildenafil works by relaxing the blood vessels that supply the penis. This improves blood flow, making it easier to achieve and maintain an erection. When you first start taking sildenafil, you may not experience effects straight away. Your doctor may recommend you try sildenafil several times over a period of a few weeks to see if it works for you.

How effective is sildenafil?

Sildenafil is very effective with at least 2/3 of men reporting an improvement with use, and up to 84% of men reporting improvement in studies using a dose of 100mg. Erectile dysfunction can vary a lot between people and it’s common to trial several doses or several different therapies before finding the one that works best for you. To help you, an ED Trial Pack is available that contains a selection of the most popular ED medications at a range of doses.

How long does sildenafil take to work?

Sildenafil takes 30–120 minutes to work, and is advised to be taken one hour before sexual activity. Sildenafil does not automatically give you an erection, but it makes it easier to obtain an erection following sexual stimulation. When you first start taking sildenafil, it can take a while to adjust, so you may need to try taking it over a few weeks before you see any effects.

How long does sildenafil last?

Sildenafil typically lasts for 4–5 hours, with some studies reporting effects for up to 12 hours. This does not mean that you will have an erection for this whole time period, as you still require sexual arousal and stimulation to trigger an erection.

Sildenafil misuse

Sildenafil is a convenient and effective treatment for erectile dysfunction but can be dangerous if overused or if used recreationally. It is important to remember that sildenafil is a prescription drug and should never be used if not prescribed to you personally by a doctor. Purchasing any medication from an unregistered source is extremely risky, as you can never be sure of what exactly you are taking, so though it may seem like a hassle, it is well worth obtaining it on prescription. Sildenafil should never be used where it is not necessary, as improper use puts you at risk of increased side effects and dependence.


Active ingredients

The active ingredient in sildenafil is sildenafi citratel.

Inactive ingredients

The inactive ingredients in sildenafil are calcium hydrogen phosphate anhydrous, cellulose microcrystalline, croscarmellose sodium, silica colloidal anhydrous, magnesium stearate, lactose monohydrate, hypromellose 15cP, titanium dioxide (E171) and triacetin.

Note that inactive ingredients may differ depending on the manufacturer.

Which ingredients can cause an allergic reaction?

While Sildenafil is not known for causing an allergic reaction in users, if you are using the medication for the first time you should look out for these signs. Signs of an allergic reaction are: hives, difficulty breathing, swelling of the face/lips, and dizziness. Seek medical help straight away if you notice any of these after taking Sildenafil.


How to take sildenafil?

Always take sildenafil as instructed by a doctor or pharmacist, who will also instruct you on your dosage. Swallow one tablet whole with a glass of water approximately an hour before sexual activity. Sildenafil may take longer to work if you have just eaten a heavy or fatty meal. If you feel that your dose is too weak or too strong, speak to your doctor who may alter your dosage. Do not take sildenafil more than once per day.

Sildenafil starting dosage

The recommended starting dose of sildenafil is 50mg, taken as required, up to once a day. Your doctor will normally recommend you trial this on several occasions over a period of a few weeks. If you find it’s not working as expected, speak to your doctor who may increase your dose. The maximum dose is 100mg up to once per day. Exceeding this dose will not increase its effectiveness, but will increase the risk of side effects.

Can sildenafil tablets be crushed or divided?

Sildenafil tablets should be swallowed whole with a glass of water and should not be crushed or split.

Can sildenafil be taken daily?

Sildenafil can be taken daily if necessary, but should not be taken more than once a day. It is only effective in the instance of sexual arousal.

Side Effects

Sildenafil side effects

Like all medications, sildenafil can cause side effects in some patients. If you experience any of the following serious side effects, stop taking sildenafil and seek medical help immediately:

  • An allergic reaction with symptoms including wheezing, difficulty breathing and swelling of the eyelids, face, lips or throat
  • Chest pain. If this occurs, get into a semi-sitting position and try to relax, and do NOT use nitrates (e.g. GTN spray) to treat your chest pain
  • Prolonged (>4 hours) or painful erections
  • Sudden decrease or loss of vision
  • Serious skin reaction including severe peeling, swelling, blistering of the mouth, genitals or skin around the eyes, and fever
  • Seizures or fits

Headaches may affect greater than 1 in 10 people who use sildenafil. 

Other common side effects (affecting up to 1 in 10 people) are:

  • Nausea
  • Flushing, particularly of the face
  • Indigestion
  • Visual disturbance including colour distortion and blurred vision
  • Congested nose
  • Dizziness

Uncommon side effects (affecting up to 1 in 100 people) are:

  • Vomiting
  • Skin rash
  • Eye irritation
  • Bloodshot or red eyes
  • Seeing flashes of light
  • Visual brightness
  • Light sensitivity
  • Watery eyes
  • Pounding or rapid heartbeat
  • High or low blood pressure
  • Muscle pain
  • Sleepiness
  • Reduced sense of touch
  • Vertigo
  • Ringing in the ears
  • Dry mouth
  • Blocked sinuses
  • Sinusitis
  • Upper-abdominal pain
  • Gastro-oesophageal reflux disease
  • Blood in the urine
  • Pain in the arms or legs 
  • Nosebleed
  • Feeling hot or tired

Rarely (less than 1 in 1,000 people), the following side effects may be experienced:

  • Fainting
  • Stroke
  • Heart attack
  • Irregular heartbeat
  • Temporary decreased blood flow to parts of the brain
  • Tightening of the throat
  • Numb mouth
  • Bleeding at the back of the eye
  • Double vision
  • Abnormal sensation in the eye
  • Swelling of the eye or eyelid
  • Small particles or spots in your vision
  • Seeing halos around lights
  • Dilation of the pupil of the eye
  • Discolouration of the white of the eye
  • Penile bleeding
  • Blood in the semen
  • Dry nose
  • Swelling of the inside of the nose
  • Feeling irritable
  • Sudden decrease or loss of hearing


Do NOT take sildenafil if you:

  • Are allergic to sildenafil or any of the other ingredients
  • Have low blood pressure
  • Have unstable heart disease or unstable angina
  • Have severe heart or liver problems
  • Have recently had a stroke or heart attack
  • Have a family history of degenerative eye diseases such as retinitis pigmentosa
  • Have ever had a condition involving loss of vision due to damage of the optic nerve from insufficient blood supply known as non-arteritic ischemic optic neuropathy (NAION)
  • Are taking nitrites e.g. for angina
  • Use “poppers” (butyl nitrate)
  • Take a guanylate cyclase stimulators (used to treat pulmonary hypertension)

You should inform your doctor and take particular care when taking sildenafil if you:

  • Have leukaemia or multiple myeloma
  • Have problems with your heart e.g. aortic stenosis, arrhythmia, cardiomyopathy
  • Have hypertension (high blood pressure)
  • Currently have a stomach ulcer
  • Have a bleeding problem such as haemophilia
  • Have an anatomic abnormality of your penis e.g. angulation, Peyronie’s disease
  • Have sickle cell anaemia

Drug interactions

Before taking sildenafil, tell your doctor or pharmacist if you are taking any other medications, including those purchased over the counter without a prescription. 

Do not take sildenafil along with:

  • Medicines containing nitrates, e.g. glyceryl trinitrate (GTN), isosorbide mononitrate, nicorandil, amyl nitrate
  • “Poppers” which contain amyl nitrate or butyl nitrate
  • Guanylate cyclase stimulators e.g. riociguat, used to treat pulmonary hypertension

In particular, speak to your doctor if you take:

  • Other treatments for erectile dysfunction
  • Other PDE-5 inhibitors e.g. for the treatment of pulmonary arterial hypertension
  • Alpha-blockers such as doxazosin, prazosin
  • Medications used to treat HIV e.g. ritonavir
  • Anti-infective medications such as ketoconazole, itraconazole, erythromycin, cimetidine
  • Grapefruit juice

How to cope with sildenafil side effects?

The most common side effects of sildenafil use is headache, which is reported to occur in more than 10% of users. Headaches can be managed with hydration and over-the-counter painkillers, such as paracetamol or ibuprofen, where necessary. If you experience facial flushing, try and stay cool by applying a cool compress, breathing deeply and trying to relax. If any of these side effects are particularly severe or prolonged, or if you frequently experience stomach upset when taking sildenafil, speak to a doctor or pharmacist for advice. A doctor may recommend an alternative ED treatment.

Sildenafil and alcohol

While sildenafil doesn’t directly interact with alcohol, drinking alcohol can inhibit your ability to get an erection. In order to experience the best results of sildenafil, it is recommended that you limit the amount of alcohol you drink.

Can I take sildenafil with other ED medications?

Sildenafil should not be taken in combination with other erectile dysfunction medications unless specifically advised by a doctor.

Do recreational drugs affect sildenafil?

It can be dangerous to take sildenafil with recreational drugs, including stimulants such as ecstacy or cocaine, hallucinogens such as LSD and former-legal highs such as mephedrone. Sildenafil should NOT be taken in combination with poppers (butyl or amyl nitrates), as this can have a dangerous effect on your blood pressure and heart.

Treatment Options

Sildenafil vs Viagra

Viagra is the brand name of sildenafil used for treatment of erectile dysfunction. Both contain the active ingredient sildenafil and work in exactly the same way, although generic sildenafil is significantly cheaper.

Why choose sildenafil?

Sildenafil (brand name Viagra) is the most well-known and popular treatment for erectile dysfunction. Generic sildenafil is significantly cheaper than the branded Viagra and works in exactly the same way. Alternative ED medications have since been developed and are available on prescription in the UK, including tadalafil, vardenafil and Spedra (Avanafil). Different treatments may be better suited to different people, and a doctor will be able to advise you which is likely to work best for you.

Brands of sildenafil

A doctor will write a prescription for this medication using the medical name “sildenafil”, but a pharmacist is free to supply any available brand. Viagra is a brand name for sildenafil prescribed for the treatment of ED in the UK, and Revatio is the brand name sildenafil used for the treatment of pulmonary hypertension. The brand name Viagra Connect can be purchased without a prescription in the UK. The brand Kamagra is not legal in the UK, and can therefore only be purchased illegally through websites that are not registered pharmacies. Doing so runs the risk of purchasing counterfeit medication which can be dangerous.

Alternative treatments

In the UK, most treatments for erectile dysfunction require a prescription, however, Viagra Connect has recently become available over the counter. Like sildenafil, tadalafil (Cialis) and vardenafil (Levitra) are PDE-5 inhibitors that work by increasing blood flow to the penis in the event of sexual stimulation. Tadalafil (Cialis) has a longer action time, and can remain effective for up to 36 hours. Spedra is the newest PDE-5 inhibitor (ED medication) and takes as little as 15 minutes to take effect and has a similar duration of action to sildenafil and vardenafil.


Is sildenafil safe for long-term use?

Sildenafil is safe for long-term use, although this may lead to psychological dependency. Erectile dysfunction often has a psychological component, such as anxiety, depression or stress, and continued use of treatments such as sildenafil may mask these issues and prevent the patient from pursuing more effective, long-term help.

Is sildenafil a cure?

Sildenafil will not cure erectile dysfunction, the root cause of which is often psychological. However, it can help to relieve the stress and anxiety associated with ED in the short term and improve the physical symptom of erectile dysfunction.

Can women take sildenafil?

There is little evidence to suggest that sildenafil has any effect on female libido or sexual enjoyment and it is not licenced for arousal disorders in women. However, it can be used to treat pulmonary hypertension in women.

Is it safe to buy sildenafil online?

It is safe to buy sildenafil online from a registered pharmacy such as Dr Felix. It is a prescription-only medication and should not be purchased online through any website that does not require a private prescription. However, Viagra Connect, which contains 50mg sildenafil is available over the counter without a prescription.

Can I buy sildenafil without a prescription?

Generic sildenafil is only available in the UK with a prescription and should not be purchased prescription-free online. Viagra Connect is the only version of sildenafil which is available over the counter without a prescription in the UK.

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