Is Viagra safe? What you need to know

An estimated 30 million people in the United States live with erectile dysfunction (ED). Contrary to popular belief, ED doesn’t just impact older adults–roughly 1 in 4 people newly diagnosed with ED are younger than 40. No matter how old you are, if you’re affected by ED, you’ve probably heard of Viagra. 

The FDA (US Food and Drug Administration) approved Viagra (generic name sildenafil citrate) in 1998 to treat ED, and it has since become one of the top-prescribed treatments in the men’s health space. But despite its popularity, many wonder—is Viagra safe? 

Viagra is a safe and effective medication to treat erectile dysfunction when used as prescribed by a healthcare provider. Taking too much Viagra or taking Viagra too frequently, however, may increase your risk of side effects. If you’re considering talking to your doctor about “the little blue pill,” make sure you discuss your health history and additional medication with your healthcare provider. 

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Is Viagra safe? 

Viagra and its generic sildenafil are safe if you follow your healthcare provider’s instructions. That said, taking Viagra more frequently or using a higher dose than you are prescribed can be dangerous or lead to more side effects. Taking other medications or supplements may also affect how safe Viagra is for you. 

Like all prescription drugs dispensed in the United States, the treatment didn’t become available to the public for the treatment of ED until the FDA deemed Viagra safe and effective, following a robust clinical trial and approval process. 

How does Viagra work?

Erections are pretty complex, and many things can prevent them from working as easily as you might hope. The active ingredient in Viagra is sildenafil, a type of drug called a PDE-5 inhibitor that improves blood flow to the penis. It works by blocking the effects of an enzyme called PDE-5 (phosphodiesterase-type 5), allowing more blood flow to reach the penis, and making for a stronger erection.

Another common question when exploring ED treatment options is, “How long does it take for Viagra to work?” The answer mostly depends on you and your sex life—Viagra can only help you get hard and stay hard if you are already aroused, and it won’t work unless you are sexually stimulated. Generally, it takes about 30–60 minutes to kick in.

How often can you take Viagra? 

Viagra is meant to be taken on an as-needed basis, and knowing when to take Viagra is a key factor in determining how well the treatment will work for you. It’s meant to be taken on an as-needed basis about an hour before sexual activity, but the treatment may be taken anywhere from 30 minutes to 4 hours before sexual activity.  

You should take your medication exactly as prescribed at the recommended dose. The little blue pill comes in three dosage strengths (25 mg, 50 mg, and 100 mg). Your provider may adjust your dose based on how well it works or any side effects you may be experiencing. Regardless of your dose, you should only take a maximum of one Viagra pill in any 24-hour period. You can take this prescription drug on an empty stomach or following a meal. However, if you eat a high-fat meal, it may take longer for Viagra to start working.

If you accidentally take more Viagra than your prescription calls for, you should seek medical attention to avoid potential complications.

What are the side effects of Viagra? 

Evidence suggests that long-term Viagra use is relatively safe, and complications are generally rare among people taking Viagra as prescribed.

All medications come with a risk of certain side effects, though, and Viagra is no exception. According to the product label, the most common side effects are:

• Headache

• Facial flushing

• Pain or discomfort in the upper abdomen (dyspepsia)

• Abnormal or blurred vision

• Nasal congestion

• Back pain

• Aching muscles

• Nausea

• Dizziness

• Rash

An erection lasting more than 4 hours (priapism) is an uncommon but serious side effect of Viagra and requires emergent treatment to prevent permanent penis damage. Ultimately, your healthcare provider is your best source of medical advice and for knowing how to manage Viagra's side effects.

Who should not take Viagra?

ED affects both older and younger people alike. While Viagra is considered safe for most people with ED, some factors and health conditions may make people more prone to bad side effects. You should never take Viagra with nitrates or nitrates, as this drug combination can lead to a dangerous drop in blood pressure. People who should not take Viagra, or may be cautioned against taking it due to the risk of serious side effects, include:

• People with certain heart conditions that are considered too risky for sexual activity

• Those who take certain classes of medications, including alpha-blockers and anti-hypertensives

• People with a history of low blood pressure, irregular heartbeat, or heart failure

• Anyone who has experienced a stroke or heart attack in the past six months

The best way to know if Viagra is right for you is to speak to a healthcare provider about your concerns, especially if you have heart conditions.

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How we reviewed this article

Every article on Health Guide goes through rigorous fact-checking by our team of medical reviewers. Our reviewers are trained medical professionals who ensure each article contains the most up-to-date information, and that medical details have been correctly interpreted by the writer.

Current version

March 27, 2023

Written by

Allison Gilchrist

Fact checked by

Chimene Richa, MD

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About the medical reviewer

Chimene Richa, MD

Dr. Richa is a board-certified Ophthalmologist and medical writer for Ro.