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A Complete Guide to Sildenafil Side Effects

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You may know Sildenafil by its brand name, Viagra. Sildenafil Citrate is an effective medicine for Erectile Dysfunction.

Your doctor may recommend Sildenafil if you have erection problems. But you may need the medicine only when you have continuous trouble having or holding an erection.

If it happens once in a while, it is usually not a cause for concern.

Even though Sildenafil is an effective medication, it may have some side effects.

You should always inform your doctor about prevailing health conditions and medicines you take.

This information will help them prescribe a suitable ED treatment for you and prevent side effects from Sildenafil.

Let us understand more about Sildenafil side effects.

Side effects of Sildenafil

Side effects of SildenafilSource: Getty_images
Sildenafil side effect

Generally, low doses of Sildenafil work for most people. Sildenafil may cause side effects rarely due to its short-term use in low doses.

But you do not have to worry if you do have them. Mostly, these are short-term side effects that go away on their own. They do not need medical attention.

The most common side effects of Sildenafil (Viagra) include headache, Nausea, and flushing.

You may need immediate medical help if you have serious side effects like fainting, chest pain, heart problems, or Priapism.

Common side effectsSerious side effects
HeadacheLow blood pressure
FlushingAllergic reaction
Stuffy noseBurning and itching during urination
DizzinessBlurred vision or severe, sudden loss of vision
IndigestionRinging in ears or hearing problems
Difficulty differentiating blue or green colorsShortness of breath that worsens
Sensitivity to lightHeart attack
Muscle painPriapism

You should note that this is not an exhaustive list of Sildenafil side effects. Seek medical help if you face any or all of these side effects.

According to your doctor, the benefit of the medicine may be more than the risk of side effects. For this reason, they may prescribe Sildenafil Citrate.

It is not necessary that you will have any or all of these adverse effects. 

Most of these side effects go away on their own. Contact your healthcare provider if they start to bother you or persist for a long time.


Headache is one of the most common side effects of Sildenafil Citrate. They are mostly temporary and go away on their own.

16% to 28% of users report headaches after taking Sildenafil, as per FDA data. Viagra (Sildenafil) may induce migraine headaches in some people, as per research.

Headaches that may result from Sildenafil may include cluster headaches or migraines. Cluster headaches usually occur on one side of the head and are extremely painful.

A common cause of headaches is dehydration. You should drink a lot of water to avoid dehydration from Sildenafil.

Taking painkillers or using a hot or cold compress may help reduce the intensity of headaches.

As mentioned the most commonly reported side effect of Sildenafil (Viagra) is headaches, often dubbed ‘Viagra headache’. Dive deeper into this topic by reading this articleCan You Really Have Viagra Headache?

Do not take Ibuprofen and Sildenafil together without consulting your doctor to avoid drug interactions.


The same FDA data shows that about 10 to 18% of people taking Sildenafil may experience flushing.

Sildenafil affects the blood vessels in the penile region to increase blood flow and treat erection problems. 

But the effects of Sildenafil may not be limited to blood vessels in the penile region. The medicine may affect blood vessels in other parts of your body.

This may dilate the blood vessels close to your skin’s surface, making it look red or feel warm to the touch.

A lower dose of Sildenafil may help to avoid this side effect.

The likelihood of experiencing flushing increases when combining alcohol with Sildenafil. For a thorough understanding, check out this articleIs It Safe To Use Sildenafil And Alcohol Together?

Dyspepsia (Indigestion)

Dyspepsia (Indigestion)Source: suprV

According to a 2018 paper, Dyspepsia is one of the most frequently reported adverse reactions of Sildenafil (Viagra).

A common name for Dyspepsia is indigestion. People with this condition may experience stomach pain, bloating during and after meals, and feelings of over-fullness.

Other symptoms of Dyspepsia include heartburn, acid reflux, and excessive burping.

Discover which foods should not be taken while using Viagra (Sildenafil) in this comprehensive articleKnow All About Beverages and Foods to Avoid When Taking Viagra


Priapism is an erection lasting for 4 hours or more. It is a severe Sildenafil side effect that needs immediate medical help.

According to a 1999 report, Sildenafil can induce Priapism. But the study participant has a history of ED and took injection therapy earlier.

Combining injection therapy and Sildenafil may cause this side effect. Sildenafil alone is not likely to cause Priapism in most cases.

Avoid taking injection therapy with Sildenafil to avoid prolonged and painful erections.

Vision changes

Sildenafil may cause vision problems such as blurred vision, increased sensitivity to light, or even vision loss in rare cases.

A 2021 research suggests Sildenafil may increase intraocular pressure in the eye or cause Nonarteritic Ischemic Optic Neuropathy (NAION).

Another report suggests that using Sildenafil may cause minor temporary vision changes. Rarely, it may even lead to sudden vision loss.

  • is a condition in which there is a loss of blood flow to the optic nerve which can cause sudden loss of vision

    Low blood pressure

    Sildenafil relaxes blood vessels in the penile region to increase blood flow. This helps treat erection problems.

    But the effects of Sildenafil may not be limited to blood vessels in the penile region and affect other parts of the body.

    This can lead to a fall in blood pressure levels. Extremely low blood pressure can cause you to faint or result in a heart attack.


    Many people may have a stuffy nose or Rhinitis after taking Sildenafil

    Rhinitis is a reaction to allergens that may enter the body and trigger the immune system to release histamines. It can result in irritation and swelling of the mucous membrane.

    Most participants of a 2006 study indicated that they have nasal congestion/ obstruction after using Sildenafil.

    Hearing problems

    Sildenafil can cause hearing issues such as ringing in the ears or hearing loss.

    A 2011 study suggests that using PDE-5 inhibitors such as Sildenafil may induce Sensorineural hearing loss.

    There needs to be more awareness among doctors about this side effect to prescribe proper treatment.

    Heart problems

    Sildenafil does not play a direct role in causing heart problems. Yet several studies suggest that heart problems may be a serious side effect of Sildenafil.

    As mentioned above, the use of Sildenafil can lower your blood pressure levels. Extremely low blood pressure can cause a heart attack or stroke.

    As per a paper, Sildenafil can cause serious cardiovascular events. These events occur rarely and mostly in at-risk population.

    For those curious about the safety of taking Sildenafil, find clarity in this articleUnveiling the Truth: Is Sildenafil Safe for Your Health?

    The bottom line

    Sildenafil is one of the first ED medications to get FDA approval for treating Erectile Dysfunction symptoms.

    Though effective, Sildenafil can sometimes result in side effects. 

    They may be short-term such as headaches or flushing, which usually go away on their own.

    Or it may cause serious side effects such as Priapism which may need immediate medical attention.

    Long-term Sildenafil side effects may include hearing or vision problems. One of the most common side effects of Sildenafil is low blood pressure.

    Low blood pressure can cause further problems, such as heart attacks.

    Consult your doctor before taking Sildenafil. They will help you determine if it suits you and how to use it to avoid side effects.

    Not sure of which doctor to consult for ED concerns? This article has got you covered– “Erectile Dysfunction Doctors: Know the Top 3 Experts“.

    Frequently Asked Questions

    How to reduce side effects of Sildenafil?

    Most Sildenafil side effects go away on their own and do not need medical attention. Resting or lying down may help reduce the intensity of headaches, flushing, or dizziness.
    Serious side effects such as Priapism or low blood pressure may require immediate medical help.

    How long do Sildenafil side effects last?

    Most side effects of Sildenafil start to go away after 1 hour, while almost all of them go away within 12 hours of consumption.
    Seek medical help if the side effects persist for a long-time or bother you.

    Who should not take Sildenafil?

    People with underlying health conditions such as heart or liver conditions or blood pressure problems should consult a doctor before taking Sildenafil.
    Those who take heart medicines or nitrates should not take Sildenafil to avoid the risk of potential side effects.

    Is Sildenafil safe for sperm?

    The results of a study indicate that a single oral dose of 100 mg of Sildenafil does not have any adverse effect on sperm.

    What is Viagra peak time?

    Viagra (Sildenafil) can start to show effects within 30 minutes of consumption and may show peak effects within 1 hour.
    These effects can differ from person to person due to differences in several physical and psychological factors.

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    Photo of author Janet Fudge
    Janet Fudge is a highly skilled and experienced pharmacologist who serves as a contributing writer for With a strong academic background from a premier US University and a passion for helping others, Janet has become a trusted voice in the pharmaceutical world. After completing her Doctor of Pharmacy degree, Janet embarked on a successful career in the pharmaceutical industry, working with various clients, including hospitals, retail pharmacies, and drug manufacturers. Her in-depth knowledge of pharmacology and dedication to patient-centered care has led her to excel in her field. As a writer for, Janet uses her wealth of expertise to provide readers with accurate, reliable, and up-to-date information on various topics related to medicine and healthcare. Her engaging writing style and ability to break down complex topics into easily digestible content make her a valuable resource for healthcare professionals and the general public.
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