What Are the Side Effects of Viagra?

dr zoe miller medical editor

Medically reviewed by

Dr Zoe Miller

Last reviewed: 14 Mar 2025

Viagra is a medicine used to treat erectile dysfunction (ED), which happens when there is difficulty getting and maintaining an erection. Viagra belongs to a group of medicines called phosphodiesterase type 5 (PDE5) inhibitors which work by increasing blood flow to the blood vessels in the penis.

Like any medication, Viagra does come with a risk of potential side effects, but these are usually mild and short-lived, and not everyone experiences them.

Understanding the possible side effects of Viagra tablets and who is most at risk can help you decide if it’s the right medication to treat your ED. This guide explores the most common side effects of Viagra, how likely you are to get them, and tips for how to avoid them.

Contents
Man checking the side effects of Viagra on his phone and laptop
 

What are the most common side effects of Viagra?

The most common side effect of Viagra is a headache. Headaches may be experienced by more than 1 in 10 people who take Viagra for erectile dysfunction.

Other side effects of Viagra are less common (1 in 10 people may experience) include:

  • nausea (feeling sick)
  • facial flushing (redness)
  • hot flushes
  • indigestion
  • changes to vision, including colour tinge, blurred vision and visual disturbance
  • stuffy nose
  • dizziness

These side effects of Viagra tablets are mild and often go away within a few hours.

Uncommon side effects of Viagra can affect up to 1 in every 100 people taking it. These include:

  • vomiting
  • skin rash
  • irritation, pain, watery, red, or bloodshot eyes
  • visual brightness, flashes of light or light sensitivity
  • pounding or rapid heartbeat
  • high blood pressure (hypertension) or low blood pressure
  • muscle pain
  • tiredness or feeling sleepy
  • reduced sense of touch
  • vertigo
  • ringing in the ears
  • dry mouth
  • blocked sinuses
  • runny or stuffy nose or sneezing
  • pain in the upper tummy
  • heartburn caused by gastro-oesophageal reflux disease
  • blood in pee (urine)
  • arm or leg pain
  • nosebleeds
  • feeling hot
  • hypersensitivity/allergic reaction
  • chest pain

Dr Zoe Miller, medical editor

Most people don’t experience Viagra side effects. When they do occur, they’re usually mild and can be managed effectively at home. However, you may be more at risk of experiencing side effects if you’re on a higher dose of Viagra (100mg). Your doctor will monitor your usage, and you should let them know if you get side effects.” – Dr Zoe Miller, Medical Editor.

Are there any serious side effects from taking Viagra?

There are some side effects of Viagra that can be serious, but these are very uncommon (1 in 1000 experience).

Severe side effects of Viagra include:

  • allergic reaction
  • chest pain
  • a prolonged erection that lasts for more than 4 hours and may be painful (priapism)
  • sudden decrease or loss of vision
  • sudden decrease or loss of hearing
  • serious skin reactions
  • seizures or fits
  • sudden cardiac death
  • myocardial infarction
  • ventricular arrhythmia
  • atrial fibrillation
  • unstable angina
  • throat tightness
  • nasal oedema
  • nasal dryness
  • cerebrovascular accident
  • transient ischaemic attack

If you experience any of these side effects, especially a painful erection, you should stop taking Viagra straight away and seek medical assistance. If you have a heart condition and feel chest pain after taking Viagra, call and speak to a healthcare professional straight away. If you think you are experiencing an allergic reaction, cardiac, or seizure, this is a medical emergency and you should call 999 right away.

Can Viagra cause mental health side effects?

Viagra is not commonly associated with mental health side effects, but some patients can experience mild anxiety or mood changes. Viagra can also uncommonly cause a rapid heartbeat, which may make you feel anxious.

More commonly though, any changes in mental wellbeing are caused by ongoing frustration or psychological factors related to erectile dysfunction. Psychological ED is caused by stress, anxiety, or emotional concerns.Viagra can address physical symptoms but may not resolve psychological causes.

If you’re experiencing rare mental health side effects of Viagra, or have a mental health condition that gets worse when you try to have sex, such as mood changes, persistent anxiety, or depression, speak to your doctor or a trusted healthcare professional as soon as possible.

Is Viagra safe?

Yes, Viagra is a safe treatment for erectile dysfunction for most people. As with any medication though, the effects can vary from person to person. Some people may be sensitive to Viagra’s active ingredient sildenafil and experience side effects with the standard 50mg dose. Others might find that even the highest dose of Viagra (100mg) has little to no side effects, and in some cases, Viagra may not work at all.

Your age, as well as certain health conditions and medications, can also affect the way Viagra works in your body and can cause more side effects. You should speak to your doctor for guidance if you’re considering treatment.

Taking too much Viagra, especially over the maximum dose of 100mg, can increase your risk of side effects and can be dangerous. View our guide to safe Viagra doses for more information.

If you’re unsure about whether Viagra is suitable for you, you can complete our confidential online health questionnaire and one of our ZAVA doctors will let you know whether Viagra is the right treatment option for you.

Does Viagra have any long-term side effects?

Viagra is not associated with any long-term side effects. Most side effects with Viagra are minor and short-lived. This is because you only need to take Viagra just before you want to have sex, rather than a treatment that is taken every day. Side effects should stop if you stop using Viagra to treat erectile dysfunction and if you do get them, they should calm down within 4 to 6 hours after your dose.

Am I likely to get side effects from Viagra?

You are unlikely to have side effects from Viagra, although they’re sometimes possible. When side effects are described as common, it means they affect up to 1 in every 10 people taking the medication. This means that the majority of people taking Viagra will not experience them.

Who is more susceptible to Viagra side effects?

Certain medical conditions and medications can make you more likely to experience persistent or dangerous side effects from Viagra. You should not take Viagra if you have:

  • had a recent stroke, heart attack, or low blood pressure
  • been prescribed nitrates for angina or have taken nitric oxide-containing medications like amyl nitrite (poppers), as these can cause a dangerous drop in blood pressure
  • been prescribed alpha-blockers, typically used to treat high blood pressure or an enlarged prostate (these can interact with Viagra and cause dizziness when standing)
  • liver disease or liver problems
  • severe kidney problems
  • some eye conditions like retinitis pigmentosa or non-arteritic anterior ischemic optic neuropathy (NAION)
  • blood disorders such as sickle cell anaemia or a history of stomach ulcers or bleeding problems
  • have an anatomical deformity of the penis, such as Peyronie’s disease

Additionally, other medications for high blood pressure, heart disease, or diabetes may interact with Viagra, increasing the risk of side effects. Always inform your doctor of all medications and health conditions to determine if Viagra is safe for you.

Are the side effects of Viagra worse in older men?

As we age, our bodies undergo changes that can affect how we process medications like Viagra. For older adults, particularly those aged 65 and over, these changes may increase the likelihood of experiencing side effects. Here’s what you need to know:

1. Slower metabolism

With age, your body’s ability to metabolise drugs slows down. This means that Viagra may stay in your system longer, potentially leading to a higher risk of side effects such as headaches, dizziness, or flushing. For this reason, doctors often recommend starting with the lowest dose (25mg), for men aged 65 or older to reduce these risks.

2. Increased sensitivity to medications

Older adults may be more sensitive to the effects of Viagra, particularly its impact on blood pressure. Viagra works by dilating blood vessels to improve blood flow, which can also cause temporary drops in blood pressure. This may lead to dizziness or fainting, especially in men with existing cardiovascular conditions.

3. Potential drug interactions

Many older men who experience side effects of Viagra also take medications for conditions like high blood pressure, heart disease, or diabetes. Some of these medications, such as nitrates or alpha-blockers, can interact with Viagra and increase the risk of serious side effects like dangerously low blood pressure.

Your doctor will consider the above factors when deciding whether Viagra is suitable for you, and may recommend alternative treatments if it’s not right for you.

How to reduce the side effects of Viagra tablets

  • clipboard

    Take Viagra exactly as instructed by your doctor or pharmacist.

  • viagra tablets

    Do not take more than the recommended dose.

  • call

    Inform your doctor if you experience side effects; they may adjust your dosage.

  • clock

    Do not take Viagra more than once a day.

  • man with erectile dysfunction

    Avoid excessive alcohol, as it can make it harder to maintain an erection.

  • warning sign

    Avoid grapefruit juice while taking Viagra.

  • headaches

    Stay hydrated if you experience headaches while taking Viagra.

  • tablets

    Do not combine Viagra with other erectile dysfunction medicines.

  • tick box

    Share your medical history with your doctor before taking Viagra.

  • allergy

    Do not take Viagra if you are allergic to sildenafil or its ingredients.

  • doctors

    Inform your doctor of all medications to avoid drug interactions.

Is there an alternative erectile dysfunction treatment that has no side effects?

As with all medicines, there are no alternative erectile dysfunction medications that have no guaranteed side effects.

There are other treatments available for erectile dysfunction that have different side effects to Viagra. Alternative medical ED treatments available from ZAVA include tadalafil, Cialis and Levitra. If you’re concerned about side effects of erectile dysfunction treatment, complete our online health questionnaire and a ZAVA online doctor can advise on what treatment might be suitable for you.

If you’re experiencing erectile dysfunction, you may find some lifestyle changes helpful, such as:

  • reaching and staying at a healthy weight
  • avoiding smoking
  • eating a healthy diet
  • drinking no more than the recommended maximum amount of alcohol
  • getting plenty of exercise
  • avoiding or reducing cycling if you regularly cycle more than 3 hours a week
  • reducing stress levels

If you have erectile dysfunction that is linked to another medical condition (for example diabetes), you should speak to your doctor for advice. Erectile dysfunction can also be a side effect of other medications.

Another tablet-free treatment for erectile dysfunction is a penis pump. A penis pump is a non-medical option to treat erectile dysfunction, which can also be used alongside ED medication. It’s important to mention that a penis pump can sometimes cause side effects such as coldness, numbness, bruising, and discomfort. You should speak to your doctor if you have any questions or concerns.

Conclusion

Viagra is a well-established and effective treatment for erectile dysfunction, but like all medications, it comes with the potential for side effects. Most of these side effects are mild, temporary, and manageable with simple adjustments, such as staying hydrated, avoiding alcohol or grapefruit juice, and taking over-the-counter painkillers. While serious side effects are rare, it’s important to understand the risks, especially for older adults or those with existing medical conditions or taking other medications.

Whether you’re exploring Viagra or alternative erectile dysfunction medications, you can find a range of treatments tailored to your needs with ZAVA.

Viagra side effects FAQs

Are side effects different for generic or over-the-counter Viagra?

There are no differences in side effects for generic or over-the-counter Viagra (Viagra Connect).

Viagra is a brand name for the medicine called sildenafil. Both generic and over-the-counter Viagra contain the same active ingredient, sildenafil citrate. The only difference is that you can only get Viagra Connect in 50mg doses, while Viagra can be prescribed up to 100mg.

Are there more side effects with Viagra 100mg?

Viagra 100mg is the highest dose of sildenafil available, which means you have a higher concentration of the medication in your body. This brings with it an increased risk of experiencing side effects like headaches, nausea or dizziness.

If you’ve been prescribed Viagra 100mg and are experiencing persistent or bothersome side effects, talk to your doctor about potentially reducing your dose or finding an alternative ED treatment. You should never take 100mg of Viagra without the approval of a healthcare professional.

Can you get side effects from expired Viagra?

Taking expired Viagra can lead to unpleasant side effects. This is because medications lose potency over time due to chemical changes, affecting not only how well they work, but also their safety.

While taking expired Viagra is unlikely to cause severe symptoms, there is a risk that the degraded medication could lead to side effects including digestive discomfort, headaches, and dizziness.

To ensure your treatment is safe and effective, always check the expiry date on your medication packet and properly dispose of any expired tablets.

Does Viagra stress the heart?

Viagra primarily works by relaxing blood vessels and increasing blood flow, which can cause a slight drop in blood pressure. While this effect is generally safe for healthy individuals, those with underlying cardiovascular conditions (such as a recent heart attack, severe heart disease, or low blood pressure) may experience strain during sexual activity.

Viagra should never be taken with nitrates (‘poppers’) or certain medications for heart problems, as this combination can lead to dangerous drops in blood pressure. You should always consult your doctor before using Viagra if you have any heart conditions or concerns about your ED treatment.

Why do I have a stuffy nose after taking Viagra?

A stuffy nose is a fairly common side effect of Viagra. This occurs because the medication relaxes blood vessels, which can also affect the nasal passages, leading to mild congestion. However, it’s usually temporary and goes away within a few hours.

Drinking plenty of water and using saline nasal sprays can help to alleviate this symptom. If your stuffy nose is persistent or bothersome, speak to your doctor about adjusting your dose or exploring alternative treatments.

Can I take paracetamol for a headache after taking Viagra?

Yes, you can take painkillers like paracetamol and ibuprofen if you experience a headache as a side effect of Viagra. Usually, these headaches will be mild, but you should let your doctor know if they’re recurring or severe.

If you’re unsure about whether painkillers interact with other medications that you’re taking as well as Viagra, it’s best to check with your doctor or pharmacist whether it’s safe for you to use.

How does alcohol affect Viagra side effects?

Drinking alcohol while taking Viagra can increase the likelihood and intensity of certain side effects. Both alcohol and Viagra can cause vasodilation (widening of blood vessels), which can lead to a temporary drop in blood pressure. This may result in dizziness, lightheadedness, or fainting, especially when standing up too quickly. Alcohol can also intensify other side effects, such as headaches, flushing, and nasal congestion.

As well as this, excessive alcohol consumption can make it harder to achieve or maintain an erection, counteracting the effects of Viagra. To reduce side effects and get the best results, we recommend limiting alcohol intake when taking Viagra.

Does Viagra cause side effects in partners?

A common concern among men taking Viagra is whether the medication could affect their partner. Rest assured, Viagra does not pass into semen in significant amounts, so it is highly unlikely to cause any side effects for your partner during sexual activity.

Viagra’s active ingredient, sildenafil, works within your body to increase blood flow to the penis, making it easier to get and maintain an erection. This process does not involve transferring the medication to your partner.

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Medically reviewed by:
Dr Zoe Miller Medical Editor
Accreditations: MBChB, BSc

After completing her first degree, she went on to study graduate-entry medicine at Warwick University. After graduating as a doctor, she worked within the West Midlands in Urology, Respiratory Medicine, Infectious Disease, and Psychiatry before transitioning into a full-time medical communications role.

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Last reviewed: 14 Mar 2025






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