Viagra

Viagra is a prescription medication for erectile dysfunction. It contains the active ingredient sildenafil, which helps increase blood flow to the penis during sexual stimulation. This makes it easier to get and keep an erection. Viagra is one of the most well-known and widely prescribed treatments for ED and has been used safely for over 25 years.

Although Viagra helps improve erections, it does not increase your sex drive or cure the underlying cause of erectile dysfunction. If your ED is caused by an underlying health condition, such as diabetes, high blood pressure, or cardiovascular disease, it's important that this is also managed.

Viagra is a phosphodiesterase type 5 (PDE-5) inhibitor. This means it blocks the PDE-5 enzyme, allowing the blood vessels in the penis to relax and widen so more blood can enter, making it easier to get and maintain an erection.

When you're sexually aroused, your body goes through a certain process to get an erection, producing a chemical called cyclic GMP (cGMP). This relaxes the smooth muscles in the blood vessels of your penis. However, the PDE-5 enzyme breaks down cGMP quickly.

Viagra temporarily blocks PDE-5, so cGMP can remain active for longer. This means the blood vessels stay relaxed for longer, improving blood flow and making an erection easier. Because Viagra enhances your body's natural response to sexual stimulation, it will not cause an erection on its own. You'll still need to be sexually aroused for it to work.

How long does Viagra last?

Viagra usually lasts for up to 4 hours after taking a dose. This does not mean you'll have an erection for 4 hours. Instead, it means you'll be more likely to get an erection during this time if you're sexually stimulated.

How long does Viagra take to work?

Viagra starts working within 30 to 60 minutes of taking a tablet. You should take Viagra around an hour before you expect to have sex.

Taking Viagra after a large or high-fat meal may delay how quickly it starts working.

How effective is Viagra?

Large-scale studies of Viagra followed more than 8,000 people aged 19 to 87 who had a range of different causes for their ED. The effectiveness at each dose was as follows:

• 62% – 25mg
• 74% – 50mg
• 82% – 100mg
• 25% – placebo

Viagra has also been proven to treat erectile dysfunction caused by mental and physical health conditions, such as diabetes, high blood pressure, and depression. The safety and effectiveness of Viagra were maintained throughout long-term studies.

“If Viagra does not work the first time you take it, do not give up straight away. You may need to try it on several separate occasions before deciding whether it's right for you. Taking it correctly, allowing enough time for it to work, and making sure you're sexually aroused can all improve how well it works.” – Dr Brenda Ikeji, Medical Editor

Viagra should be taken exactly as your doctor prescribes. For the best results:

• swallow 1 tablet whole with water
• take it 60 minutes before sexual activity
• make sure you're sexually stimulated, as Viagra will not work without arousal
• avoid taking more than 1 tablet in any 24 hours

If you've been prescribed Viagra for the first time and it does not work straight away, do not increase your dose yourself. Speak to your doctor before making any changes to your treatment.

When should I take Viagra?

The best time to take Viagra is around 1 hour before you plan to have sex. Some men notice it starts working after around 30 minutes, while for others it may take a little longer. Planning ahead gives the medication enough time to reach effective levels in your bloodstream.

Viagra can be taken with or without food, but a large or high-fat meal may delay how quickly it works. If you want it to work within an hour, it's best to take it on an empty stomach or after a light meal.

How often can you take Viagra?

Viagra is taken as needed, rather than every day. You should never take more than 1 dose in 24 hours. Taking extra tablets will not make the medication work better and is likely to increase your risk of serious side effects.

If you need treatment more regularly, speak to your doctor. Depending on your lifestyle, another erectile dysfunction treatment which lasts longer may be more suitable.

Viagra dosages

Viagra is available in 3 dosages:

• 25mg – may be recommended if you have certain medical conditions, such as liver or kidney problems
• 50mg – most people start on 50mg
• 100mg – usually only required if 50mg does not work or is not strong enough after trying it on 8 different occasions

The right dose depends on how well the medication works for you, whether you experience side effects, your age, and any other health conditions you have.

Like all medications, Viagra can cause side effects. When side effects do happen, they're usually mild, temporary, and improve as the medication leaves your body.

Common side effects may affect up to 1 in 10 people, and include:

• headaches
• facial flushing or hot flushes (a sudden feeling of warmth, usually in the face, neck, or chest)
• indigestion or an upset stomach
• a blocked nose
• feeling dizzy
• feeling sick (nausea)
• changes to your vision, such as blurred vision, a blue colour tinge, or other temporary visual disturbances

These are the side effects reported most often and are usually mild. Because Viagra is only taken when needed, any side effects generally last for a few hours rather than continuing every day.

Uncommon side effects may affect up to 1 in 100 people, and include:

• being sick (vomiting)
• skin rash
• eye irritation, sore eyes, red eyes, or watery eyes
• increased sensitivity to light, seeing flashes of light, or brighter-than-normal vision
• a fast or pounding heartbeat
• high or low blood pressure
• muscle aches
• feeling sleepy or unusually tired
• reduced sensation or numbness
• dizziness with a spinning sensation (vertigo)
• ringing in the ears (tinnitus)
• dry mouth
• blocked sinuses, a runny nose, sneezing, or inflammation of the nasal passages
• pain in the upper part of your abdomen or heartburn (acid reflux)
• pain in your arms or legs
• blood in your urine
• nosebleeds
• feeling hot

If these side effects are ongoing or severe, speak to your doctor or pharmacist straight away.

Rare side effects may affect up to 1 in 1,000 people and include:

• an irregular heartbeat
• temporary reduced blood flow to part of the brain (transient ischaemic attack)
• a tight feeling in your throat
• numbness in your mouth
• bleeding behind the eye
• double vision
• reduced sharpness of vision
• unusual sensations in the eye
• swelling of the eye or eyelid
• seeing floating spots, specks, or halos around lights
• enlarged pupils
• changes in the colour of the white of the eye
• bleeding from the penis
• blood in the semen
• a dry nose or swelling inside the nose
• feeling irritable
• sudden loss of hearing or a sudden decrease in hearing
• fainting
• heart attack
• stroke

You should speak to a doctor or call 999 in an emergency if you get these side effects.

Serious side effects

Stop taking Viagra and call 999 or go to A&E if you get any serious side effects from Viagra.

Uncommon serious side effects (may affect up to 1 in 100 people) include:

• severe allergic reaction – symptoms can include sudden wheezing, difficulty breathing, feeling faint or dizzy, or swelling of your face, lips, tongue, throat, or eyelids
• chest pain – stop sexual activity immediately, sit in a semi-upright position, try to relax, and do not take nitrate medications to treat the chest pain, as this can be dangerous

Rare serious side effects (may affect up to 1 in 1,000 people) include:

• an erection lasting longer than 4 hours (priapism) – a prolonged or painful erection which needs immediate medical treatment to prevent permanent damage to the penis
• sudden loss of vision or a sudden decrease in vision in one or both eyes
• severe skin reactions – these may include widespread blistering or peeling of the skin, blisters around the mouth, eyes or genitals, and fever
• seizures (fits)

How long do Viagra side effects last?

Most Viagra side effects improve within a few hours as the medication is broken down and leaves your body. Because Viagra usually remains active for around 4 hours, side effects often settle by this time or shortly afterwards. Occasionally, mild effects such as a headache or flushing may last a little longer.

If your side effects are severe, do not improve, or happen every time you take Viagra, speak to your doctor. They may recommend reducing your dose or changing to a different erectile dysfunction treatment.

What to do if you get Viagra side effects

Most mild side effects can be managed at home. Depending on your symptoms, it may help to:

• drink plenty of water if you develop a headache
• avoid drinking excessive amounts of alcohol
• eat a lighter meal before taking Viagra
• rest until symptoms improve
• avoid driving or operating machinery if you feel dizzy or your vision is affected

If you experience severe side effects, chest pain, an erection lasting more than 4 hours, or sudden vision or hearing changes, call 999 or get to A&E straight away.

Viagra is a safe and effective treatment for erectile dysfunction when it’s prescribed to you. However, it’s not suitable for everyone. Before taking Viagra, your doctor will review your medical history and any medications you are taking to make sure it is safe for you.

Who should not take Viagra?

Viagra may not be suitable if you:

• are allergic to sildenafil or any of the other ingredients in Viagra
• have been advised to avoid sexual activity because of a serious heart condition
• have severe heart or liver disease
• have recently had a heart attack or stroke
• have very low blood pressure
• have certain rare inherited eye conditions, such as retinitis pigmentosa
• have ever experienced vision loss caused by non-arteritic anterior ischaemic optic neuropathy (NAION)
• are under 18 years old

Viagra is only licensed to treat erectile dysfunction in adult men and should not be taken by women.

Tell your doctor before taking Viagra if you have:

• heart disease or problems with your circulation
• high blood pressure that is not well controlled
• a stomach ulcer or a bleeding disorder, such as haemophilia
• a condition that affects the shape of your penis, such as Peyronie's disease
• illnesses that increase your risk of prolonged erections, including sickle cell anaemia, leukaemia, or multiple myeloma
• kidney or liver problems
• any existing eye conditions or changes to your vision

Your doctor can decide whether Viagra is a suitable erectile dysfunction treatment for you.

Medications that may interact with Viagra

Some medications can interact with Viagra, making it less effective or increasing the risk of side effects. Tell your doctor about any prescription medicines, over-the-counter treatments, or herbal remedies you are taking before starting treatment.

Medications that may interact with Viagra include:

• nitrate medications used to treat angina and nitric oxide donors, such as amyl nitrite ("poppers") – these should never be taken together with Viagra
• riociguat, which is used to treat pulmonary hypertension
• alpha-blockers used for high blood pressure or an enlarged prostate
• medications used to treat HIV, including ritonavir and saquinavir
• certain antifungal medicines, such as ketoconazole or itraconazole
• certain antibiotics, including erythromycin and clarithromycin
• other medications containing sildenafil, including treatments for pulmonary hypertension
• other erectile dysfunction medications, such as tadalafil, vardenafil, avanafil, or alprostadil

Always let your doctor know if you start any new medication while taking Viagra.

Viagra is a prescription-only medication in the UK, so you'll need a prescription from a registered healthcare professional before you can buy it. You can get Viagra online from trusted websites like Asda Online Doctor, or in some cases, from your GP.

Can I buy Viagra online?

Yes. You can order Viagra online from Asda Online Doctor by completing a short medical questionnaire. One of our doctors will review your answers to check whether Viagra is suitable for you.

If your treatment is approved, you can choose to:

• collect your medication from your local Asda Pharmacy
• have it delivered to your home in discreet packaging, with free standard delivery

You'll also have access to ongoing doctor support through your secure patient account if you have any questions during treatment.

Can I buy Viagra over the counter?

No. Viagra is only available with a prescription. If you're looking for an over-the-counter alternative, Viagra Connect contains the same active ingredient (sildenafil 50mg) but is available without a prescription after a consultation with a pharmacist. Unlike Viagra, Viagra Connect is only available in the 50mg strength.

Can I get Viagra on the NHS?

Viagra may be available on the NHS for some men with erectile dysfunction, but eligibility is limited. You’re more likely to be prescribed the generic version, called sildenafil tablets. These are the same medication, just without branding.

NHS prescribing is generally reserved for people with certain medical conditions, such as diabetes, multiple sclerosis, Parkinson's disease, spinal cord injuries, or for those who have had prostate surgery. If you do not meet the NHS prescribing criteria, you can still get Viagra privately through Asda Online Doctor or another doctor service.

If Viagra is not suitable for you, or you would prefer a different erectile dysfunction treatment, there are several alternatives available. They all work by increasing blood flow to the penis but differ in how quickly they work and how long their effects last.

At Asda Online Doctor, we offer:

• sildenafil – the generic version of Viagra, containing the same active ingredient at a lower cost
• Hezkue spray – contains sildenafil like Viagra but comes as a mouth spray, so gets to work faster (in as little as 12 minutes)
• Viagra Connect – contains sildenafil 50mg and is available without a prescription following a pharmacy consultation
• Cialis (tadalafil) – lasts for up to 36 hours, making it suitable if you prefer more spontaneity
• Spedra (avanafil) – can start working in as little as 15 minutes
• vardenafil – another PDE-5 inhibitor that may be suitable if other treatments have not worked well
• Vitaros cream (alprostadil) – a cream applied directly to the penis rather than taken as a tablet

If you're unsure which erectile dysfunction treatment is right for you, our doctors can recommend the most suitable option based on your medical history, lifestyle, and treatment preferences.

Do Viagra tablets become less effective over time?

No. During long-term clinical trials, the safety and effectiveness of Viagra were maintained. However, there’s a small chance that it may become less effective for you over time. This could be caused by several things, including age, the cause of your ED, other health conditions, or other medications that you take. If this happens, you may need a higher dose or a different ED treatment.

Can women take Viagra?

No. Women should never take Viagra, as it’s only for men with ED. It could be dangerous to take sildenafil as a woman, especially if you’ve got any health conditions or could be pregnant. It also will not have the same effect because it works to enhance the natural way that men get an erection, and sexual stimulation for women is different. Speak to a doctor if you’re a woman and are struggling with a low sex drive or dryness in the vagina.

Can I split Viagra tablets?

No, you should not split Viagra tablets, as it’s not known how much of the active ingredient you’re taking. This could make it less effective. If you think your dose is too high, speak to your doctor about taking a lower dose.

Does Viagra make you last longer?

No. Viagra cannot make you last longer in terms of how long it takes to ejaculate (come). It can help you keep an erection longer, which may mean that sex lasts longer. Sometimes ED can happen alongside another condition called premature ejaculation (PE).

If you ejaculate quickly and cannot control it, you may have PE. Sometimes treating ED is enough to help treat PE, but you can also take medication for PE if you need it. If you’re not sure, speak to your doctor about your symptoms.

Can you drink alcohol while taking Viagra?

Yes, you can drink alcohol while taking Viagra, but it's best to keep it to a minimum. Drinking large amounts of alcohol can make it more difficult to get or keep an erection, which may reduce how well Viagra works.

Alcohol can also increase the chance of side effects such as dizziness, headaches, flushing, and low blood pressure. If you feel light-headed after taking Viagra, avoid drinking more alcohol and sit or lie down until your symptoms improve.

If you're planning to take Viagra, limiting your alcohol intake can help you get the best results from your treatment.

Is Viagra safe?

Yes, Viagra is a safe and well-established treatment for erectile dysfunction when it's prescribed and taken as directed. It has been used by millions of men worldwide for over 25 years and has been extensively studied in clinical trials.

Before prescribing Viagra, your doctor will check that it's suitable for you by reviewing your medical history and any medications you're taking. This is important because Viagra is not safe for everyone, especially in people taking nitrates or those with certain heart conditions.

Like all treatments, Viagra can cause side effects, but these are usually mild and temporary. Serious side effects are rare, and most people take Viagra without any problems. Taking the correct dose, avoiding medications that interact with Viagra, and following your doctor's advice can help reduce the risk of side effects and make sure you get the best results from treatment.