Is Sildenafil Safe?

Is sildenafil safe? For most men, sildenafil (Viagra^®) is a safe and effective treatment for ED (erectile dysfunction) when used as prescribed. However, like all medications, it comes with potential side effects and drug interactions.

Most adverse effects are mild and temporary. For some, especially those with preexisting medical conditions, sildenafil can cause more serious side effects.

We’ll break down how sildenafil works for treating ED, who shouldn’t take it, and how to ensure you’re using it safely to improve your sex life.

In the ’80s, researchers tested a medication called sildenafil citrate for treating high blood pressure (hypertension) and angina (chest pain). While the treatment appeared promising for these purposes, it was more potent in — ahem — another more sensitive area of the body. 

Apparently, many of the participants were embarrassed to disclose to the research staff that they were experiencing erections during the trial.

Though sildenafil was intended to relax and dilate blood vessels around the heart, it’s also active in the blood vessels around the penis — which is how it supports erections. Talk about getting more than you bargained for.

Needless to say, researchers took an unexpected pivot and decided to investigate sildenafil as a treatment for erectile dysfunction. After all, if it was causing erections among men who weren’t necessarily looking for that effect — imagine what it could do for those struggling to stay hard.

After further trials, sildenafil citrate was approved by the U.S. Food and Drug Administration (FDA) in 1998. It’s the active ingredient in brand-name Viagra, now a very well-known drug for ED.

Treating ED is the most common use for Viagra. Sildenafil is also used in different dosages to treat pulmonary arterial hypertension under the brand name Revatio^®.

Sildenafil is in a class of drugs called phosphodiesterase 5 inhibitors (PDE5 inhibitors), along with other meds like Cialis^® (tadalafil), Stendra^® (avanafil), and Levitra^® (vardenafil).

These are the gold-standard drugs for the treatment of erectile dysfunction. Studies show that just one dose of Viagra has a 70 to 80 percent success rate for treating ED.

PDE5 is an enzyme that regulates blood flow to many parts of the body, including the soft erectile tissues inside the penis. It can keep the smooth muscle in the arteries supplying the penis from relaxing, which can reduce blood flow.

PDE5 inhibitors increase blood flow to your penis, resulting in longer, harder erections when you experience sexual stimulation.

How Long Does It Take for Sildenafil to Work?

Your next question is probably when it’ll start working and how long sildenafil lasts. We get it — this is important stuff when planning the logistics of your evening.

Most of the time, Viagra begins to work 30 to 60 minutes after taking it. 

It may work more slowly if you take it after eating a fatty meal (like a burger and fries), so make sure you strategically pop that little blue pill based on your plans.

As for how long it lasts, the packaging insert says Viagra has a half-life of four hours.

No, this doesn’t mean you’re still going to have a hard-on at that point. It just means the drug will still be in your system but not necessarily at a high enough concentration to have noticeable effects.

For the best results, plan to have sex within these first four hours of taking sildenafil.

When used as directed to treat erectile dysfunction, sildenafil is safe and effective for most men. However, like any drug, it has potential side effects and drug interactions to consider.

Common Sildenafil Side Effects

The most common sildenafil side effects include: 

• Headaches, affecting up to 28 percent of men who use it

• Muscle aches and back pain

• Nasal congestion due to its dilating effects on blood vessels

• Lightheadedness or dizziness

• Flushing of the skin (like red cheeks)

• Heartburn or indigestion

• Nausea, though this is only reported by a small percentage of men who use it

• Reduced blood pressure when combined with certain other medications

• Blurred vision or otherwise abnormal vision, though this is usually mild and temporary

If you take a dose of sildenafil above 100 milligrams (mg), you’ll have a higher risk of experiencing any of these side effects.

Rare Sildenafil Side Effects

Other more serious but less common side effects of Viagra have also been reported, such as:

• Priapism, a prolonged erection that lasts several hours and can become painful

• Sudden hearing loss

• Rare permanent loss of vision due to optic nerve damage (known as what is non-arteritic anterior ischemic optic neuropathy)

If you experience any of these potentially serious side effects, seek immediate medical attention.

If your sildenafil side effects are severe (or even if they just impact your life too much), your provider may recommend an alternative drug or another ED treatment. 

Sildenafil acts on the blood vessels in your penis, so you may wonder if it has any worrisome effects on your cardiovascular system as a whole.

There have been reports of stroke, heart attack, and irregular heartbeats among those who take Viagra. However, there’s currently no solid evidence directly linking sildenafil to heart attacks in men. 

The fact is, people with ED have a higher likelihood of having heart disease — and vice versa. For example, problems with both your penis and your heart can be associated with a vascular condition affecting blood flow.

Is Sildenafil Safe If You Have a Heart Condition?

PDE5 inhibitors like sildenafil may not be safe for folks who have existing heart problems. It’s unclear if it is safe for those who’ve had a heart attack, stroke, or irregular heartbeat within the last six months. Talk to your healthcare provider if you have abnormal blood pressure at rest or a history of heart failure or unstable angina.

As a vasodilator, sildenafil widens blood vessels throughout your entire body — which is to say, areas other than your penis. So it may actually lower blood pressure. This drop is generally so small that most men don’t notice it, even those taking medication for high blood pressure.

Still, a drop in blood pressure can be dangerous — even life-threatening — if you have existing heart-related concerns.

Additionally, sildenafil can interact with drugs called nitrates, which are commonly prescribed for heart conditions. We’ll discuss this more next.

Finally, sexual activity of any type can put a strain on your heart. If you have an existing heart condition, the physical stress of having sex may increase your risk of heart attack, stroke, or other cardiovascular events.

Certain types of medications shouldn’t be taken with sildenafil due to potentially serious interactions, like:

• Nitrates (such as nitroglycerin, isosorbide dinitrate, or isosorbide mononitrate) used to treat congestive heart failure and chest pain

• Alpha-blockers, which are prescribed for hypertension and benign prostatic hyperplasia (BPH)

• Recreational drugs called “poppers,” which may contain nitrites

• Ketoconazole, a drug used to treat fungal infections

When nitrate-containing drugs are used with sildenafil, they can cause a sudden and severe drop in blood pressure. This may make you feel dizzy or (more seriously) could cause you to pass out.

Ketoconazole can inhibit certain proteins in your liver. This can result in higher-than-normal levels of sildenafil in your body, which may lead to headaches, flushing, and dizziness.

Sildenafil can even potentially trigger a heart attack or stroke when combined with certain other medications.

The best way to avoid adverse effects is to disclose all your prescription, over-the-counter, and recreational drug use to your healthcare provider before you begin using Viagra. 

Additionally, certain preexisting medical conditions may increase your risk of experiencing side effects from using sildenafil. Let your provider know if you have:

• A deformed penis shape or condition called Peyronie’s disease (characterized by a curved penis)

• Heart issues or have previously had a stroke or heart attack

• Blood cell-related conditions, such as multiple myeloma, sickle cell anemia, or leukemia

• High blood pressure, low blood pressure, or pulmonary arterial hypertension (PAH)

• An eye-related condition like retinitis pigmentosa, which can increase your risk of other vision problems when using ED medications

• Bleeding problems or stomach ulcers

• Liver and kidney problems, including being on dialysis

Sildenafil isn’t suitable for everyone. To ensure it’s safe for you, be open with your medical provider about your health history.

Dealing with ED can understandably trigger a range of emotions. Frustration, anxiety, depression, and shame can impact your quality of life.

It might be tempting to throw caution to the wind and try anything just to regain control. However, you’re wise to go over your situation with a professional and understand your options.

Sildenafil is highly effective and safe when used as directed, but that doesn’t mean you should disregard potential risks.

To reduce your risk of side effects and dangerous drug interactions, adhere to the following tips for how to take Viagra for best results:

• Take it as prescribed. Sildenafil is most commonly prescribed in once-daily doses between 25 and 100 milligrams for ED. Your healthcare provider will determine the best dosage based on various factors — more doesn’t necessarily equal better.

• Use it strategically. Sildenafil is most effective when taken at least 30 minutes to one hour before sex. For most people, it can provide ED relief for around four hours. Take this into account when planning to use sildenafil for sex.

• Know the potential side effects of sildenafil. Sildenafil isn’t for everyone. It can interact with other medications and put your health at risk. It may also lead to side effects, like dizziness, prolonged erection, or visual changes.

• Communicate with your provider. We know how awkward it can be to talk about your sexual activity with, well, most people. Still, make sure your healthcare provider is aware of any preexisting health conditions you have, as well as any supplements or drugs you use.

If you’re unsure how to take sildenafil properly or whether it’s even right for you, consider talking to a healthcare professional online for medical advice.

Is Viagra safe? Yes, sildenafil and brand-name Viagra are usually a safe and effective drug for ED management when taken as prescribed.

Just keep the following things in mind if you’re considering using sildenafil to improve your sex life:

• Understand the potential side effects. Viagra can cause side effects, interact with other medications, and be dangerous for those with certain health conditions. Speak openly with your healthcare provider about your lifestyle and health history before starting Viagra or any other erectile dysfunction medication.

• Know there are other options. In some cases, another ED drug — such as tadalafil or avanafil — may be a better fit for you. Alternatively, you might be interested in Hims hard mints, chewable ED meds containing the same active ingredients as other ED prescriptions in personalized dosages.

• Identify other factors that may be causing ED. ED affects an estimated 30 million men in the U.S. alone, and many experience psychological ED. This is when things like depression, anxiety, or sexual performance anxiety get in the way of your erections.

ED can be frustrating for everyone involved. Fortunately, living with ED doesn’t need to be a life sentence.

Take our free virtual sexual health assessment to start exploring your treatment options.