Viagra (Sildenafil) Side Effects: A Complete Guide
You have a big date night planned and want everything to go smoothly. But if you deal with erectile dysfunction (ED) on occasion — no big deal, a lot of guys do — you might want to have some sildenafil (better known by its brand name Viagra®) on hand.
Nicknamed the “little blue pill,” Viagra is the most well-known erectile dysfunction medication out there. But despite how ubiquitous it is, many guys probably don’t stop to think about sildenafil side effects.
While sildenafil is generally safe and effective for men, there’s still a possibility of experiencing mild side effects, as well as rarer but more serious effects.
Whether this is your first time using sildenafil, you’re a regular user or it’s just been a while since you last needed it, it’s always good to know as much as you can about a medication — including the side effects.
Most of the Viagra side effects are mild and transient (meaning they tend to fade away as the medication exits your body), although some can become serious if you use other medications or have a pre-existing health condition.
Below, we’ve listed the most common side effects of sildenafil and Viagra precautions you should know about.
The Most Common Side Effects of Sildenafil
The original Viagra uses were to treat hypertension (high blood pressure) and angina (chest pains due to high blood pressure). However, its use has expanded to treat sexual dysfunction in men — namely ED.
Sildenafil is a type of prescription drug known as a PDE5 inhibitor. Sildenafil and other PDE5 inhibitors prevent the function of an enzyme called phosphodiesterase type-5 that’s responsible for the size of blood vessels in the body — including the penis.
By blocking the PDE5 enzyme, sildenafil helps increase blood flow to your penis for stronger erections.
Viagra, like every medication, has the potential to cause side effects. Typically, these side effects occur while the medication is active in your body (generally three to five hours), although some may continue for several hours after Viagra’s active effects wear off.
The most common side effects of sildenafil are generally very mild, with more than 94 percent of patients feeling satisfied with the treatment and reporting few side effects — which makes sildenafil a safe ED medication.
You’re more likely to experience sildenafil side effects if you take a higher dose, although they’re still generally mild and short-lasting.
Regardless of your dosage, the most common side effects of sildenafil you’re likely to experience include:
Back pain
Nasal congestion (rhinitis)
Dizziness
Facial flushing
Indigestion or heartburn (dyspepsia)
Nausea
Visual changes (blurred vision or sensitivity to light)
Low blood pressure
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Less Common, More Serious Viagra Side Effects
Although serious side effects from Viagra are highly uncommon, they can still happen. Viagra has several of these rare side effects, including allergic reaction, priapism and damage to the nerve that delivers electrical impulses from your eyes to your brain.
It’s important to pay close attention to the symptoms of these side effects and notify your healthcare provider if you experience any issues.
Priapism (Prolonged and/or Painful Penile Erection)
Priapism is a serious condition in which you experience a painful and prolonged erection that lasts for several hours without any sexual stimulation. It can result in permanent damage to the erectile tissue inside your penis if it’s left untreated.
Compared to other Viagra side effects, priapism is very uncommon. However, priapism can cause many severe complications, including ischemia, hypoxia, cavernosal acidosis and permanent damage to the erectile tissue in your penis.
If you develop a painful penile erection that persists for several hours, especially with little or no sexual stimulation, it’s important to seek medical advice from a healthcare professional as soon as possible.
Damage to the Optic Nerve
Although it’s extremely rare, erectile dysfunction drugs such as Viagra are linked to damage to the optic nerve, specifically nonarteritic anterior ischemic optic neuropathy (NAION).
NAION is a serious medical condition that can result in permanent damage to the eyes, including vision loss.
This issue affects a very small percentage of men who use Viagra, but having existing eye issues or a "crowded" optic disc may put you at a higher risk.
In a review published in the International Journal of Clinical Practice in 2006, researchers found that approximately 2.8 cases of NAION occur per 100,000 patient-years of Viagra use, which means it’s pretty unlikely you’ll get this rare side effect.
To reduce your risk of developing NAION, it’s important to inform your healthcare provider of any existing vision-related health issues before using Viagra, or get immediate medical attention if you experience any loss of vision while using Viagra or similar medications to treat ED.
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Sudden Loss of Hearing
An extremely small percentage of men who used Viagra have reported a condition known as sudden sensorineural hearing loss (SSHL). This condition involves damage to the inner ear that can, in some cases, cause permanent loss of hearing.
In addition to hearing loss, Viagra can cause other hearing-related conditions, such as ringing in the ears (tinnitus).
Hearing issues from Viagra are uncommon, but it’s important to tell your healthcare provider if you experience any changes in your hearing after taking Viagra, such as sudden loss of hearing or reduced hearing sensitivity.
Sildenafil Interactions & Precautions
While you may not be able to avoid some of the more common side effects of sildenafil, there are some other Viagra warnings to take note of.
Specifically, you should be aware of sildenafil drug interactions with some medications, such as those used to treat high blood pressure, heart disease and other cardiovascular health issues.
These medications can lower blood pressure when used with Viagra, so be sure to tell your healthcare provider if you’re taking any of them:
Nitrites such as nitroglycerin, isosorbide dinitrate or isosorbide mononitrate
Alpha-blockers
Recreational drugs that contain amyl nitrate (called “poppers”)
Other PDE5 inhibitors, including Revatio or other pulmonary arterial hypertension treatments
There are also a few foods to avoid when taking Viagra, including grapefruit juice, excessive alcohol or high-fat meals.
Certain medical conditions may also increase your likelihood of developing side effects from Viagra and other ED medications. To keep yourself safe while using Viagra, it’s important to inform your healthcare provider about any pre-existing conditions before you consider this medication, such as:
Any type of heart problems, such as heart failure, angina, narrowing of the aortic valve, irregular heartbeat or a previous heart attack or stroke
Pulmonary hypertension (high blood pressure in the blood vessels that supply your lungs), uncontrolled high blood pressure or low blood pressure
Any type of medical condition that affects your blood cells, such as leukemia, sickle cell anemia or multiple myeloma
Any type of eye problem or vision loss, such as non-arteritic anterior ischemic optic neuropathy or retinitis pigmentosa, a genetic eye disease
A deformed penis shape or a condition such as Peyronie’s disease, which involves damage to the tissue inside your penis
Bleeding problems, liver problems, kidney problems (especially if you’re on dialysis) or stomach ulcers
While it may be tempting to pop a pill “just in case,” using Viagra without ED can be risky and cause unwanted side effects.
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Understanding Sildenafil Side Effects
One of the downsides of taking any medication is that you might experience side effects — and Viagra (or sildenafil) is no exception. But what should you expect with the little blue pill and what might be cause for concern?
Viagra, which contains the active ingredient sildenafil citrate, is a type of medication known as a PDE5 inhibitor. This type of medication improves blood flow and helps create erections firm enough for sexual activity.
Sildenafil can cause mild side effects, the most common of which include headaches, back pain, nasal congestion, dizziness, facial flush, nausea, changes in vision and more.
More serious side effects are rare but possible. These include damage to the optic nerve, sudden loss of hearing and priapism, which is a prolonged, painful erection.
If you’re still looking for more info on Viagra, you can read this guide on how to take Viagra for the best results, or learn if you can take Viagra daily and whether there’s such a thing as too much sildenafil. And in terms of comparing Viagra vs sildenafil, know that both medications work the same way.
Viagra also isn’t the only effective erectile dysfunction medication on the market.
Vardenafil, the active ingredient in LevitraⓇ, starts working in approximately the same amount of time as sildenafil and should be taken one hour before sex.
You can also ask your healthcare provider about Stendra® (avanafil). A second-generation ED treatment, avanafil is the fastest-acting medication that produces noticeable effects in 15 to 30 minutes.
Or you can try Cialis® (tadalafil). Known as the “weekend pill,” Cialis also works quickly — it can become active within 15 minutes — and lasts for 36 hours.
While many of these medications are available as oral tablets, they also come as chewable hard mints.
If you’re interested in exploring the full range of erectile dysfunction treatments, you can check them out here or talk to a licensed healthcare provider to learn more.
This article is for informational purposes only and does not constitute medical advice. The information contained herein is not a substitute for and should never be relied upon for professional medical advice. Always talk to your doctor about the risks and benefits of any treatment or medication.