Sildenafil works when taken within 1 hour of sex and is an effective treatment for men with erectile dysfunction.(42)
Sildenafil helps treat erectile dysfunction and is manufactured by Milpharm Limited.
Sildenafil is also known by the brand name Viagra. Now you can get generic (no brand) sildenafil tablets that work exactly the same way. Sildenafil is available in 25mg, 50mg and 100mg tablets.
Order sildenafil from Asda Online Doctor by ZAVA today. Our questionnaire is quick and easy to fill out online. Then one of our doctors will check if sildenafil is right for you. Choose delivery to your home address or collection from an Asda Pharmacy.
4 tablet(s) - £14.00
8 tablet(s) - £18.00
12 tablet(s) - £35.00
16 tablet(s) - £41.00
28 tablet(s) - £65.00
4 tablet(s) - £14.50
8 tablet(s) - £22.00
12 tablet(s) - £38.00
16 tablet(s) - £43.00
28 tablet(s) - £70.00
4 tablet(s) - £20.00
8 tablet(s) - £30.00
12 tablet(s) - £50.00
16 tablet(s) - £55.00
28 tablet(s) - £90.00
Sildenafil is a medicine used to treat erectile dysfunction (ED) or impotence in adult men. You can use sildenafil to help to get and keep an erection.
Sildenafil is a PDE5 inhibitor (phosphodiesterase type 5 inhibitor). You can buy sildenafil over the counter at an Asda Pharmacy under the brand name Viagra Connect.
Is sildenafil the same as Viagra?
Sildenafil is also available as the branded medication Viagra. They both work in exactly the same way and are equally as effective. The only major difference between the 2 medications is their name.
Sildenafil relaxes your blood vessels which allows more blood to flow into your penis. This blood flow helps you keep your erection.
You should take sildenafil 30 minutes to 1 hour before you want to have sex. Sildenafil will only work if you are sexually aroused. You should only take 1 sildenafil tablet per 24 hours.
How long does sildenafil last?
The effects of sildenafil can last for up to 4-6 hours, but will normally start to wear off after 2-3 hours.
How often can I take sildenafil?
You can use 1 sildenafil tablet once a day. Even if you have been prescribed the lowest dose of 25mg, taking more than you need will not make it work faster.
What if I take too much?
The maximum dose of sildenafil is 100mg. If you take a dose higher than this, it will not make it more effective. You are more likely to have side effects if you take more than 100mg of sildenafil and may need to see an emergency doctor.
If you have taken more sildenafil tablets than advised, contact your doctor immediately. If your erection lasts longer than 4 hours (also called priapism), call 999.
Can you take sildenafil with food or drink?
You can take sildenafil with or without food. Keep in mind that a heavy meal can slow down how fast sildenafil will work.
You should not drink a large amount of alcohol before you take sildenafil, as this can make it difficult for you to maintain an erection.
What if sildenafil doesn’t work for me?
If you are unable to get an erection or keep an erection long enough with sildenafil, contact your doctor.
Sildenafil is available in 25mg, 50mg, and 100mg dosage strengths.
- The lowest dose of sildenafil is 25mg. This might be used if you have any other medical conditions or take any medicines that cause low blood pressure, or if you have had any side effects when using the standard 50mg dose.
- The standard dose for sildenafil is 50mg. You will be prescribed 50mg if you have no medical conditions, or if you have tried the 25mg dose and it was not effective.
- The highest dose for sildenafil is 100mg. This might be used if the standard 50mg dose does not work for you, as long as you did not have any side effects.
You might get side effects when you take sildenafil. These side effects usually last for a short period of time. You can speak to your doctor at any time for advice on what to do.
Common side effects of sildenafil:
- facial flushing
- increase in body temperature (hot flush)
- blurred vision
- stuffy nose
Less common side effects of sildenafil:
- eye irritation
- bloodshot or red eyes
- chest pain
- change in blood pressure
- allergic reaction
- skin rash
- dry mouth
- blood in the urine
- nose bleed
- feeling tired or hot
- changes in vision
- hearing loss
You can read the patient information leaflet inside your pack of sildenafil for more details.
There are some times when you should not use sildenafil, for example, if you:
- do not have erectile dysfunction
- are taking other treatments for erectile dysfunction, such as Cialis (tadalafil) or Levitra (vardenafil)
- have been told by a doctor not to have sex
- are a woman
- are under 18 years old
- take nitric oxide donors or ‘poppers’
- have an allergy to any of the ingredients in sildenafil
- take medicines called nitrates to treat chest pain or heart problems like angina
- take treatment for pulmonary arterial hypertension such as riociguat
- have low blood pressure
- have recently had a heart attack or a stroke
- have an inherited eye disease, such as retinitis pigmentosa
- have ever had loss of vision because of non-arteritic anterior ischaemic neuropathy (NAION)
- have severe heart disease
- have severe liver disease
You should not use sildenafil without speaking to your doctor first if you have:
- sickle cell anaemia,
- leukaemia (blood cancer)
- multiple myeloma (bone cancer)
- any deformity of the penis or Peyronie’s Disease
- a current stomach ulcer
- a bleeding disorder, such as haemophilia
- any heart problems where your heart might not be able to take extra stress
If you are unsure about anything, speak to your doctor or pharmacist. You can also message our doctors through your patient account.
The following are serious, but rare side effects. If you notice any of these, you or your partner should call 999 so you get medical attention urgently:
- an allergic reaction, like wheezing, difficulty breathing, swelling of the face, lips or throat
- chest pain: if this happens, do not use nitrate medications (given for angina)
- a prolonged or painful erection lasting more than 4 hours
- a sudden loss of vision
- seizures or fits
You should watch out for any dizziness or blurry vision after you take sildenafil. If you experience this, you should not drive or operate machinery.
Sildenafil tablets can interact with other medicines. These drug interactions affect how well sildenafil works or how the other medicines work.
Speak to a healthcare professional, such as your doctor or pharmacist, if you are taking any of the following:
- angina or chest pain treatment called nitrates, such as or glyceryl trinitrate (GTN) or isosorbide mononitrate
- HIV treatment, such as protease inhibitors
- alpha-blockers for high blood pressure, such as doxazosin or alfuzosin
- recreational drugs that affect your blood pressure, such as ‘poppers’
- certain antibiotics, such as erythromycin
You can take sildenafil with or without food. It might take a longer time for sildenafil to work if you have it with a large, fatty, greasy or oily meal.
You should avoid drinking a large amount of alcohol before you take sildenafil, as this can make it difficult for you to maintain an erection.
Sildenafil is not the only treatment available for erectile dysfunction. There are several alternatives, both medical and non-medical.
Sildenafil isn’t the only medication that can be used to treat ED. Alternatives including Viagra, tadalafil, and vardenafil are all effective treatments which are also available from Asda Online Doctor.
Sildenafil vs Viagra
Sildenafil and Viagra both contain the active ingredient sildenafil. They work in the same way and are equally as effective in treating erectile dysfunction. The only thing that differs between the 2 medications is the names.
Sildenafil vs tadalafil
Tadalafil is another generic medication which can be used to treat ED. It contains the active ingredient tadalafil and is also available under the brand name Cialis. Both sildenafil and tadalafil are classed as phosphodiesterase type 5 (PDE5) inhibitors, and work by relaxing your blood vessels, and allowing more blood to flow to your penis. The main difference between the 2 is that tadalafil normally lasts much longer than sildenafil, with the effects lasting up to 36 hours. This makes it a good alternative for people who want to be more spontaneous and not have to take a pill each time they want to have sex.
Sildenafil vs vardenafil
Vardenafil is another generic medication that is used to treat erectile dysfunction. It contains the active ingredient vardenafil and is also available under the brand name Levitra. Both sildenafil and vardenafil are part of the group of medications called phosphodiesterase type 5 (PDE5) inhibitors, and work in the same way.
There are also a range of non-medical alternatives to sildenafil which can be used to treat ED.
Penis pumps and rings
Penis pumps and rings can be effective non-medical ED treatments for some men.
- Penis pumps - work by using suction to draw blood into the penis. They can be either battery powered or manually operated, and are often a good option for men who do not want to take medication. They are not suitable for people who are taking blood thinning medication, have a condition which affects blood clotting, or have any conditions affecting their penis (such as skin problems or Peyronie’s disease).
- Penis rings - work by increasing pressure around the base of the penis, slowing the rate at which blood flows away from it. There is little evidence to suggest that they can improve the quality of erections, but they’re often used in combination with medical treatments to maximise effectiveness.
The cause of erectile dysfunction can be psychological for some men. If stress, anxiety, or depression are causing symptoms of ED, then therapy can be an effective way of treating the condition. Medical treatments such as sildenafil can be used as temporary solutions while this takes place.
Some men may find natural alternatives such as ginseng or arginine to be effective in treating ED, however there is very little evidence to support their effectiveness and they may cause unwanted side effects.
It's important to note that while natural remedies may be effective for some men, they are not a substitute for medical treatment. If you're experiencing erectile dysfunction, it's important to speak with a doctor to determine the underlying cause and develop a treatment plan that's right for you.
There are a number of lifestyle changes which can be implemented to help treat symptoms of ED. They include:
- stopping smoking
- drinking less alcohol
- regularly exercising
- maintaining a healthy weight
- completing pelvic floor exercises
Can you buy sildenafil over the counter?
No, sildenafil is only available with a prescription from a doctor
Is it safe to buy sildenafil online?
It is safe to buy sildenafil online with a prescription from a reputable source such as Asda Online Doctor. Websites which offer the medication without a prescription are illegal and not regulated, meaning there are no guarantees about the safety of what you are buying.
Can I take sildenafil with other ED medications?
It is not recommended to take sildenafil alongside other ED medications.
Sildenafil is a type of medication known as a phosphodiesterase type 5 (PDE5) inhibitor, which works by increasing blood flow to the penis. Taking multiple PDE5 inhibitors can increase the risk of serious side effects, including a sudden drop in blood pressure.
You should only ever take sildenafil or any other medication as advised by your doctor.
Is Viagra stronger than sildenafil?
Viagra and sildenafil contain the same active ingredient and, if taken at the same dose, are equally as strong/effective.
Can women take sildenafil?
No, sildenafil is only available with a prescription as a treatment for erectile dysfunction.
How can I reduce the side effects of sildenafil?
Like all medications, taking sildenafil can cause side effects. However, there are some steps you can take to reduce the risk and severity of side effects when taking sildenafil, including:
- following the dosage instructions. Your doctor will provide you with a dosage and recommendations on how frequently you can take the medication. It’s important not to exceed either of these.
- staying hydrated. Drinking plenty of water can help reduce the risk of headaches, a common side effect of sildenafil.
- avoiding alcohol and grapefruit juice. Both alcohol and grapefruit juice can interact with sildenafil and increase the risk of side effects.
- being aware of potential interactions. Sildenafil can interact with certain medications, including nitrates and alpha-blockers, which can cause serious side effects. You should tell your doctor about any other medications you are taking before using sildenafil
- reporting any side effects to your doctor. If you experience any side effects while taking sildenafil, such as headache, nausea, or dizziness, it's important to report them to your doctor. They may decide to adjust your dose or recommend a different medication.
Are there any long term effects of taking sildenafil?
Like any medication, sildenafil may cause some long term effects, particularly if taken in high doses or for a prolonged period of time. However, it's important to note that sildenafil is not intended for long-term daily use. It should only be taken as needed, according to the dosage instructions provided by your healthcare provider. If you are taking sildenafil for an extended period of time, it's important to have regular check-ups with your healthcare provider to monitor for any potential side effects and to ensure that the medication is still effective for you.
Will sildenafil make my erection bigger?
No, taking sildenafil will not increase the size of your penis. It works by increasing the blood flow to the penis, making it easier to get and maintain an erection.
Will sildenafil make me last longer in bed?
No, sildenafil will not affect how long you last in bed. It will only affect your ability to get and maintain an erection.
When does ED occur and how long does it last?
You might find that you lose an erection every so often, but normally it’s nothing to worry about. If it keeps happening, you could have erectile dysfunction (ED). This means you find it difficult to get and maintain an erection, even when you are sexually aroused.
Erectile dysfunction can occur for a variety of reasons, like:
- if you have a condition that affects the blood vessels in your body, like severe diabetes
- a side effect of certain medications such as antidepressants
- drinking more than 14 units of alcohol per week
- lifestyle factors such as smoking or obesity
If you think you have erectile dysfunction, speak to your doctor to discuss the best solution.
Which active ingredients does it contain?
The active ingredient in sildenafil tablets is sildenafil citrate (25mg, 50mg or 100mg).
The other ingredients in sildenafil tablets are calcium hydrogen phosphate anhydrous, cellulose microcrystalline, croscarmellose sodium, silica colloidal anhydrous, magnesium stearate, lactose monohydrate, hypromellose 15cP, titanium dioxide (E171), triacetin.
If you have an allergy or hypersensitivity to any of these ingredients please speak to your doctor for advice before taking sildenafil.
Check the patient information leaflet for the most up to date details on the ingredients of generic sildenafil tablets.
How should sildenafil be disposed of?
If you want to dispose of your sildenafil tablets, take them to your local pharmacy. Do not throw away your sildenafil tablets in the bin or down the drain at home.
How should sildenafil be stored?
You should store sildenafil in its original packaging, below 30°C and away from sunlight and moisture. Keep sildenafil away from children or pets.
In which pack sizes is sildenafil available?
Sildenafil 25mg is available in pack sizes of 2, 4, 8, 12, and 24 tablets.
Sildenafil 50mg or sildenafil 100mg are available in pack sizes of 1, 2, 4, 8, 12, and 24 tablets.
Information on the manufacturer
Sildenafil is manufactured by Milpharm Limited and APL Swift Services (Malta) Limited, HF26, Hal Far Industrial Estate, Hal Far, Birzebbugia, BBG 3000, Malta.
Each Viagra Connect pill is blue and rounded-diamond-shaped. Each Viagra Connect tablet is 11.2 mm x 8.1 mm. ‘Pfizer’ and ‘V50’ are written on either side of the tablets.
In which pack sizes is Viagra Connect available?
A box of Viagra Connect has blister strips containing 2, 4 or 8 pills.
Information on the manufacturer
The marketing authorisation holder for Viagra Connect is Upjohn UK Limited, Ramsgate Road, Sandwich, Kent, CT13 9NJ, UK.
Viagra Connect is manufactured by Fareva Amboise, Zone Industrielle, 29, Route des Industries, 37530 Pocé sur Cisse, France.
Further information on Viagra Connect can be reached via Medical Information at Pfizer Limited, Walton Oaks, Dorking Road, Tadworth, Surrey, KT20 7NS. Telephone: 01304 616161.
Sildenafil, Patient Information Leaflet, EMC [accessed August 2021]
Sildenafil, Summary of Product Characteristics, EMC [accessed August 2021]
Erectile dysfunction, NICE/BNF [accessed August 2021]
Sildenafil (Viagra), NHS [accessed August 2021]
Sildenafil, NICE/BNF [accessed August 2021]
(Reviews are for ZAVA UK)
Asda Online Doctor by ZAVA offers a convenient and discreet service to help men improve their erectile dysfunction. There are a number of treatments you can consider. Continue to our erectile dysfunction service page to learn about the treatment options available.