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Side Effects of Viagra and How to Manage Them
Last reviewed: 15 Sept 2026
Viagra is the most popular medication for erectile dysfunction, and is safe and effective for most men. However, it can cause side effects for less than 2% of men who use it. These side effects usually aren’t serious and most go away after a few hours.
If you’re worried about getting side effects from Viagra, we have a few tips for keeping your risk low and a doctor can help you find the right dose for you.
What's on this page?
- 1. What are the side effects of Viagra?
- 2. How to manage common side effects of Viagra
- 3. How long do side effects last?
- 4. Are there long-term side effects?
- 5. Does a higher dose make side effects worse?
- 6. Are side effects different for generic or over the counter Viagra?
- 7. How do Viagra's side effects compare to other ED treatments?
- 8. Are side effects worse for older men?
- 9. Does drinking alcohol make side effects more likely?
- 10. How to reduce your risk of Viagra side effects
- 11. Is Viagra safe?
- 12. Does Viagra react with other medications?
What are the side effects of Viagra?
Common side effects of Viagra (affect up to 1 in 10 people):
- nausea (feeling sick)
- facial flushing (face turning red)
- hot flush (sudden feeling of heat in your upper body)
- indigestion
- your vision changing colour
- blurred vision
- visual disturbances
- stuffy nose
- dizziness
Uncommon side effects of Viagra (affect up to 1 in 100 people):
- vomiting (being sick)
- skin rash
- eye irritation
- bloodshot or red eyes
- eye pain
- seeing flashes of light
- things looking brighter than normal
- light sensitivity
- watery eyes
- a pounding heartbeat
- rapid heartbeat
- high blood pressure
- low blood pressure
- muscle pain
- feeling sleepy
- A reduced sense of touch
- vertigo (feeling things are moving or spinning around)
- a ringing in your ears
- dry mouth
- blocked or stuffy sinuses
- inflammation of the lining of the nose (symptoms include runny nose, sneezing and a stuffy nose)
- pain at the top of your stomach
- gastro-oesophageal reflux disease (acid reflux, symptoms include heartburn)
- blood in urine (pee)
- pain in the arms or legs
- nosebleed
- feeling hot
- feeling tired
Rare side effects of Viagra (affect up to 1 in 100 people):
- fainting
- stroke
- heart attack
- irregular heartbeat
- temporary decreased blood flow to parts of the brain
- feeling of tightening of the throat
- a numb mouth
- bleeding at the back of the eye
- double vision
- reduced sharpness of vision
- abnormal sensation (strange feeling) in the eye
- swelling of the eye or eyelid
- seeing small particles or spots in your vision
- seeing halos (rings of colour) around lights
- dilation of the pupil of the eye (your pupil looking bigger)
- discolouration (colour change) of the white part of your eye
- penile bleeding
- blood in semen
- a dry nose
- swelling of the inside of the nose
- feeling irritable
- having trouble hearing or losing hearing completely
What are the serious side effects of Viagra?
If you get any of the following serious side effects, or signs of an allergic reaction, you should get emergency medical help by calling 111 or 999 or see the NHS page on emergency medical services.
Serious side effects:
An allergic reaction:
- Sudden wheezing or chest tightness
- Trouble breathing or dizziness
- Swelling of the eyelids, face, lips, or tongue
- Chest pain
- Ongoing painful erections
- Vision getting worse or loss of vision
Serious skin reactions:
- Severe peeling and swelling
- Blistering around the mouth, genitals, and eyes
- Fever
Does Viagra Cause Blood Pressure Problems?
Yes, Viagra can cause changes in blood pressure for some men, and both high and low blood pressure are listed as uncommon side effects of taking Viagra.
Studies show that Viagra does drop blood pressure in men who take it, whether they already have blood pressure problems or not. This drop is considered to be ‘clinically insignificant’, which means it’s not going to cause health problems for most men. This effect Viagra has on blood pressure is not surprising since it was discovered by accident when scientists were looking for new blood pressure treatments. This change in blood pressure is related to how Viagra works and is part of the reason why Viagra makes it easier to get erections.
Can Viagra affect your heart health?
Viagra can cause a mild, temporary drop in blood pressure, but does not usually damage the heart or cause heart disease when it is used correctly. However, it can rarely cause heart attacks, strokes, and other serious cardiovascular events, particularly in people who already have existing heart conditions or cardiovascular risk factors.
Clinical research suggests that Viagra is safe and does not increase the risk of a heart attack or sudden cardiac death. Speak to your doctor before taking Viagra if you have heart disease or another cardiovascular condition. You must not take it if you:
- have had a heart attack or stroke within the last 6 months
- have unstable angina or severe heart failure
- have very low blood pressure
- have been advised that sexual activity is unsafe
- take nitrates for chest pain, such as glyceryl trinitrate (GTN), because combining them with Viagra can cause a dangerous fall in blood pressure
Call 999 if you develop chest pain or symptoms of a stroke, such as facial weakness, difficulty speaking, or sudden weakness on one side. Do not use nitrate medication for chest pain after taking Viagra. Tell the emergency team when you took it.
Erectile dysfunction itself can sometimes be an early sign of cardiovascular disease because both conditions may result from narrowed or damaged blood vessels. If you buy Viagra or sildenafil over the counter, you should have a check-up with a doctor within 6 months of starting it to rule out other serious health conditions causing erectile dysfunction.
Can Viagra cause sudden hearing loss?
Yes, sudden hearing loss is a rare side effect of Viagra that can affect up to 1 in 1000 people. One study comparing the outcomes of hearing-related impairment across the most popular PDE-5 inhibitors found that sildenafil (Viagra) had the lowest rate of disability at 8.14% compared to 40% for avanafil. A 2011 review found that hearing loss occurred within 24 hours of taking a PDE-5 inhibitor in 66.7%, and Viagra accounted for more than 50% of cases.
Sudden hearing loss can affect one or both ears. If you get any changes in your hearing or lose it completely, go to A&E for treatment and let the care team know you have taken Viagra. Getting fast treatment can increase the chance of recovery and prevent permanent hearing loss.
Can Viagra affect your mental health?
Yes, Viagra can affect your mental health. Anxiety is included among the possible common side effects of sildenafil in current NHS guidance. Although feelings of anxiety or low mood may also relate to erectile dysfunction, concerns about sexual performance, or worries about whether the treatment will work. It is not known to cause depression, suicidal thoughts, or other more severe mental health issues.
Erectile dysfunction and mental health can affect each other. Stress, depression, and performance anxiety can make it harder to get an erection, while repeated erection difficulties may reduce confidence and affect relationships or emotional wellbeing. Relying on Viagra for reassurance can also leave some people feeling anxious about having sex without it.
Speak to your doctor if anxiety, low mood, or erection difficulties continue. They can review your treatment, look for physical or psychological causes and discuss support such as counselling, cognitive behavioural therapy, or psychosexual therapy. Seek urgent help if you feel unable to keep yourself safe.
Can Viagra affect your fertility?
There is no clear evidence that Viagra reduces male fertility or lowers sperm count when taken as directed. A study in healthy volunteers found that a single 100mg Viagra dose did not affect sperm movement or shape.
Viagra improves erections but does not directly increase sperm production or treat most causes of male infertility. If erectile dysfunction has made intercourse difficult, successfully treating it may make conception more achievable without changing the quality of the sperm itself.
Speak to your GP or a fertility specialist if you have concerns about your sperm count or motility, or if you and your partner have not conceived after one year of regular unprotected sex. They may recommend a semen analysis and further tests rather than stopping prescribed Viagra without advice.
How to manage common side effects of Viagra
Most common Viagra side effects are mild and improve as the medication leaves your body. Practical measures such as resting, staying hydrated, and limiting alcohol may help. Speak to your doctor or pharmacist if a side effect is severe, keeps returning, or does not go away, as your dose or treatment may need reviewing.
Here are some of the practical ways you can manage the most common Viagra side effects.
How to manage Viagra headaches
You can manage headaches caused by Viagra by getting some rest, drinking plenty of water, and avoiding excessive alcohol. You can ask a pharmacist whether a painkiller, such as paracetamol, is suitable for you. Speak to your doctor if headaches are severe, happen whenever you take Viagra, or do not improve, as a lower dose may help.
How to manage facial flushing
Where possible, move somewhere cool, loosen any tight clothing, and drink cool water if your face feels warm or looks red. Avoid alcohol, hot drinks, and spicy food when you take Viagra because these may make flushing worse. Flushing usually settles without treatment, but speak to a doctor or pharmacist if it persists or concerns you.
How to manage indigestion
Try eating smaller, lighter meals and avoiding rich, fatty, or spicy foods around the time you take Viagra. Do not lie down immediately after eating. A pharmacist can recommend a suitable indigestion treatment if needed. Remember that a heavy meal may also delay how quickly Viagra starts working, so if you are going to eat, choose lighter, easy-to-digest options.
How to manage a blocked or stuffy nose from Viagra
A blocked or stuffy nose can be relieved by using a saline nasal spray, taking a warm shower, or using a humidifier. It can also help to drink enough water and avoid smoke or other irritants, especially when taking Viagra. Check with a pharmacist before using a medicated decongestant, particularly if you have high blood pressure, heart disease, or take other medications.
How to manage dizziness
If you feel dizzy when taking Viagra, sit or lie down until the dizziness passes, then get up slowly. Drink water and avoid alcohol, which can worsen dizziness and lower your blood pressure further. Do not drive, cycle, or operate machinery while dizzy. Seek medical advice if you faint or experience severe or persistent dizziness.
How to manage nausea from Viagra
Take small, regular sips of water, and choose light, plain meals until the nausea improves. Avoid rich food and excessive alcohol, which can make you feel worse. Although Viagra can be taken with food, a high-fat meal may delay its effect. Speak to a pharmacist or doctor if nausea continues, becomes severe, or is accompanied by repeated vomiting.
How to manage blurred or altered vision from Viagra
Temporary blurred vision or a blue tint to colours can occur after taking Viagra. Try to rest your eyes and avoid driving, cycling, or operating machinery until your vision returns to normal. Stop taking Viagra and seek urgent medical advice if you experience sudden sight loss, a significant visual change, or symptoms that do not resolve.
How long do side effects last?
How long Viagra side effects last varies between people and depends on the symptom experienced. In one prospective study, sildenafil-related side effects lasted an average of 3.9 hours. Sildenafil is completely removed from your system within 24 hours, so most side effects should disappear within this time.
Most common effects are temporary, but you should speak to a doctor if they do not go away or concern you.
Are there long-term side effects?
Viagra is not known to cause side effects that gradually build up with long-term use when it is taken correctly, but some rare, sudden complications can cause lasting damage. These can happen after taking any Viagra dose and are not caused by taking Viagra over a long period.
Possible lasting complications include:
- priapism – a prolonged, often painful erection lasting more than 4 hours. Without urgent treatment, it can damage penile tissue and cause permanent erectile dysfunction
- non-arteritic anterior ischaemic optic neuropathy (NAION) – a rare condition caused by reduced blood flow to the optic nerve. It can lead to sudden and potentially permanent sight loss
- hearing loss – sudden reduced hearing or deafness is a rare side effect, which can sometimes be permanent
- cardiovascular complications – heart attacks and strokes have rarely been reported after sildenafil use, particularly in people who already had cardiovascular risk factors, so it is unclear whether sildenafil, sexual activity, or an underlying condition caused the event
If you are concerned about any of these potential side effects, speak to your doctor for more advice. If you experience any of these side effects while taking Viagra, get urgent medical treatment or, in an emergency, call 999 or go to A&E.
Does a higher dose make side effects worse?
Yes, you are more likely to get side effects as the dose of Viagra goes up. However, the chance of getting side effects is less than 2% across all doses.
This table shows the percentage of men who get certain side effects from Viagra, based on the dose they take. This shows that of the small percentage of men who get side effects, 16% of them will get a headache when taking 25mg of Viagra.
Are side effects different for generic or over the counter Viagra?
No, the side effects of Viagra and over the counter Viagra Connect are the same. This is because they share the same active ingredient, sildenafil citrate.
Sildenafil, the generic version of Viagra, also has exactly the same active ingredient and dosages as Viagra, so the possible side effects and your chance of getting them will be the same.
However, note that products from different manufacturers may contain different inactive ingredients, such as colourings, coatings, or lactose. These do not change sildenafil’s recognised side effects, but someone with an allergy or intolerance may react to a particular ingredient. Check the patient information leaflet or ask a doctor or pharmacist if you know you are sensitive to an inactive ingredient.
How do Viagra's side effects compare to other ED treatments?
Viagra has similar side effects to other PDE-5 inhibitors because they all work in a similar way to treat erectile dysfunction by widening blood vessels and increasing blood flow to the penis. That means some side effects, like headaches, facial flushing, and dizziness, can occur with all of these medications.
| Viagra | Cialis | Vardenafil | Spedra | |
|---|---|---|---|---|
| Active ingredient | sildenafil | tadalafil | vardenafil | avanafil |
| Common side effects |
|
|
|
|
All erectile dysfunction medicines can potentially cause serious effects, including a prolonged erection. PDE5 inhibitors can also interact dangerously with nitrate medicines. The most suitable option depends on your health, other medications, preferred duration of action, and the side effects you experience. You can find out more about 2 of the most popular erectile dysfunction treatments in our Cialis vs Viagra guide.
Are side effects worse for older men?
They can be. Viagra side effects are the same for older and younger men, but because your body’s ability to process medication slows with age, older men may have higher concentrations of Viagra in their body, which can increase the likelihood and duration of side effects. Research shows even most men over 70 can tolerate Viagra treatment without any serious problems.
As you get older, your chance of getting other health conditions that could make Viagra unsafe does go up, so some older men may need to take lower doses of Viagra. Also as you get older your body may get less efficient at removing Viagra from your system, so side effects may last a little longer than they would for younger men.
Does drinking alcohol make side effects more likely?
Yes, alcohol does make Viagra side effects more likely. Alcohol and alcohol both widen blood vessels and can lower blood pressure, so combining them increases the chance of getting side effects. Alcohol also makes it harder for you to get and keep erections, so drinking alcohol can make Viagra less effective. When taking Viagra, it is advisable to avoid or limit your alcohol intake.
How to reduce your risk of Viagra side effects
You can reduce your risk of Viagra side effects by making sure the treatment is suitable for you, taking the recommended dose and avoiding substances that interact with sildenafil. Side effects cannot always be prevented, but the following steps can help you use Viagra safely.
1. Get a prescription from your GP or online doctor
Your doctor will check and make sure Viagra is suitable for you before prescribing your treatment. If you have any medical conditions or are taking any other medication, you may be at an increased risk of side effects, which the doctor will check for before issuing you with a prescription.
It is also important that you give them accurate information about your health and lifestyle. This will help them identify any potential contraindications and interactions.
2. Don’t drink too much alcohol
Alcohol increases the risk of certain side effects, such as low blood pressure and dizziness. It also reduces your ability to get an erection. Avoiding alcohol will help you minimise your risk of side effects and help you get the most from your medication.
3. Don’t take more Viagra than you have been prescribed
You should never exceed the dosage that your doctor has prescribed. Consult your doctor if you feel that the dosage you are taking is not high enough or is too strong.
4. Don’t mix Viagra with recreational drugs
Avoid using recreational drugs during your treatment with Viagra – some illegal or ‘legal high’ drugs interact with Viagra and taking them can be dangerous, such as amyl nitrite or “poppers”.
5. If you experience side effects, try a lower dosage
If you get Viagra side effects, you may benefit from trying a lower dosage. You can also take the tablet with food. It will take longer to take effect when taken alongside a meal but will also be less likely to cause certain side effects. Choose lighter options, rather than high-fat or heavy meals. You should speak to a doctor if you think you need a lower Viagra dose.
6. Avoid grapefruit and grapefruit juice
Grapefruit may increase the amount of sildenafil in your bloodstream, potentially increasing your risk of side effects.
7. Do not combine Viagra with other erectile dysfunction treatments
Taking Viagra with Cialis, vardenafil, Spedra or another sildenafil-containing product can cause a dangerous fall in blood pressure and other serious effects. If you feel Viagra isn’t working for you, speak to your doctor or pharmacist for advice.
8. Do not take more than one dose in 24 hours
Taking a higher or additional dose does not guarantee a better erection and increases the likelihood and severity of side effects. You should only take one dose of Viagra in a 24 hour period.
Is Viagra safe?
Viagra is a safe and effective medication for most men. Less than 2% of men get side effects from Viagra and most people who do get side effects don’t get serious ones. As long as a doctor has approved treatment for you, you can be sure it’s safe for you to use.
Does Viagra react with other medications?
Viagra can react with other medications but as long as you’ve told your doctor what medications you’re taking and they still approve treatment, it shouldn’t be a problem. Tell your doctor if you are taking any of the following:
- nitrates
- nitric oxide donors (“poppers”)
- protease inhibitors (used to treat HIV)
- alpha-blocker therapy
- riociguat used for pulmonary hypertension
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- Sildenafil 50 mg film-coated tablets, electronic medicines compendium [accessed 06 August 2026]
- Sildenafil (Viagra), NHS [accessed 06 August 2026]
- Spedra 50 mg tablets, electronic medicines compendium [accessed 06 August 2026]
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