Erectile Dysfunction Medications: How They Work, How Long They Last, and What to Expect

Erectile dysfunction (ED) affects more than 30 million men in the U.S., and for many, prescription ED medications like Viagra^®, Cialis^®, Levitra^®, or Stendra^® offer real relief. 

ED pills boost blood flow to the penis, making it easier to get and stay hard during sexual activity, but the right one for you can depend on many factors. 

Here, learn more about how ED medications work, how fast they kick in, how long they last, and what you should expect when taking them. If you think you might have erectile dysfunction, stay tuned. We’ll answer these questions below and go over all your options for ED medication.

ED drugs belong to a class of medications called PDE5 inhibitors, short for phosphodiesterase type 5 inhibitors.

How does ED medication work to treat erectile dysfunction? They help blood vessels relax so blood can flow more easily to the penis

Specifically, these drugs suppress PDE5 (an enzyme in the smooth muscle cells of blood vessels) so blood vessels widen. This can increase blood flow to the tissue inside your penis, making it easier to get an erection after sexual stimulation.

There’s a reason sildenafil, tadalafil, and other PDE5 inhibitors are some of the most common ED treatments: they work. In fact, these treatments can fully reverse erectile dysfunction in some cases.

There’s also some anecdotal evidence that ED pills can help manage premature ejaculation. But more research is needed there.

The U.S. Food and Drug Administration (FDA) has approved several medications for the treatment of erectile dysfunction, including:

• Sildenafil (the generic version and active ingredient in Viagra)

• Tadalafil (generic for Cialis)

• Avanafil (Stendra)

• Vardenafil (the active ingredient in Levitra and Staxyn^®)

Currently, these FDA-approved ED medications are prescription medications, meaning they can’t be purchased over the counter. They have to be prescribed by a doctor, urology specialist, nurse practitioner, or another sexual health professional. 

Healthcare providers often prescribe oral medications (aka “sex pills”) as a first line of defense for those facing erectile dysfunction.

But chewable ED meds like our hard mints provide a fresh and convenient solution, and they contain sildenafil and tadalafil.

Tadalafil significantly enhanced erectile function and sexual activity in men of different ages throughout clinical trials.

From the newer generation of ED drugs, avanafil has shown to be just as effective at improving erectile function as older medications like sildenafil, tadalafil, and vardenafil.

As to why Viagra is arguably the most popular ED medication? About 82 percent of those taking a 100-milligram (mg) dosage saw improvement in their erections.

On top of working effectively, these are some of the safest ED drugs, thanks to ongoing testing and approval by the FDA.

That said, there’s still a chance of experiencing side effects and risks (that come with taking any medication, really). We’ll get into that below.

Though erectile dysfunction pills work at different speeds based on their ingredients, most sexual dysfunction drugs take 30 to 60 minutes to start working with sexual stimulation.

For example, experts recommend taking Viagra one hour before sexual activity because it can take between 30 and 60 minutes for the medication to reach its highest concentration.

Cialis, on the other hand, reaches peak concentration anywhere between 30 minutes and six hours after taking it. So you’d want to take the pill two hours before sexual activity.

After something faster? The newer medication avanafil (brand-name Stendra) works the quickest: between 15 and 30 minutes. 

Regardless of the specific medication you use, it’s best to take your ED medication about an hour before you plan to have sex. Prepare ahead of time, and you’ll experience the medication’s full effects when you and your partner become intimate.

Avanafil is the only fast-working FDA-tested and approved ED drug, despite the fast-acting male enhancements being pushed these days. 

When it comes to those herbal or dietary supplements you see at gas stations or on sketchy websites, it’s not worth the risk to your health.

While people often associate the words “herbal” and “natural” as being harmless or even healthier than prescription medications, these over-the-counter products may contain counterfeit or unproven ingredients that aren’t safe or effective.

Learn more about why OTC ED drugs are risky in our article.

To understand how long an ED medication will last, you need to know its half-life. 

Half-life is how long it takes a medication to fall to half its peak concentration — essentially how long it’ll remain active in your body.

Here’s a breakdown of how long the most common ED drugs stay active in your system:

• Viagra (sildenafil) lasts three to five hours after it’s consumed.

• Cialis (tadalafil) has a half-life of 17.5 hours, meaning it lasts up to 36 hours after it’s consumed.

• Levitra (vardenafil) has a half-life of four to five hours and remains active in the body up to six hours after it’s consumed.

• Stendra (avanafil) has a half-life of three to five hours and remains active in the body for up to six hours after it’s consumed.

As you can see, vardenafil and avanafil work for about the same amount of time — and slightly longer than sildenafil. But tadalafil is by far the longest-lasting of the ED medications currently on the market.

Of course, people react differently to medications, so the duration of ED drugs can vary among men who take them.

Ask your healthcare provider for more information about the half-lives and duration of these pills. We compared Cialis versus Viagra and Stendra versus Viagra for a more detailed look at some of the more popular ED meds.

Here’s a comparison table to help you take a better look at your options:

You should be aware of the possible risks and side effects of ED meds before taking them — or any prescription drug, for that matter.

Side effects may vary slightly among these medications. But since PDE5-inhibitor medications work similarly, there are some common side effects, including:

• Mild headaches

• Dizziness

• Muscle aches or back pain

• Facial flushing

• Vision issues, including temporary blurry vision 

• Digestive issues or upset stomach

• Rhinitis (nasal congestion and a stuffy or drippy nose)

As a newer, second-generation ED med, Stendra (avanafil) may be less likely to cause side effects or other serious issues compared to older medications like Levitra.

However, just as every guy can experience different effectiveness with different medications, some may experience more or fewer side effects than others. We covered all the side effects of Viagra and common side effects of tadalafil in our guides.

The information packets and FDA guidelines for these medications recommend seeking immediate medical advice from a healthcare provider if your erection lasts longer than four hours or if an erection doesn’t go away on its own (a condition called priapism). This is a medical emergency, as it can lead to permanent penile injury if left untreated.

There are also some potentially serious side effects of ED meds, including drug interactions.

All currently available ED medications can temporarily cause slightly lower blood pressure levels because of their effects on smooth muscle tissue and blood flow. This low blood pressure is most often mild. And since it’s short-lived, it’s not usually dangerous for men’s health.

That said, if you use nitrates (like nitric oxide or nitroglycerin) for angina (chest pain) or alpha-blockers and certain other medications to treat hypertension (high blood pressure), the reduction in blood pressure caused by ED medications can be dangerous.

So if you take nitrates, it’s highly recommended that you don’t use sildenafil, tadalafil, vardenafil, avanafil, or other similar medications for erectile dysfunction.

And anyone currently being treated for or with a history of kidney disease, heart disease, heart attack, or other cardiovascular conditions should discuss treatment options with a healthcare professional.

Though the medications listed above can help men in many cases where erectile dysfunction might create problems, there are circumstances in which these pills won’t “solve” the problem. Specifically, ED medications might not be effective when the problem is psychological ED.

While ED is commonly associated with cardiovascular function, diet, weight, and other bodily issues, your mental health can intervene in your sex life. In fact, for younger men, it can be one of the most common causes of ED.

Men who deal with sexual performance anxiety, self-esteem issues, depression, sexual trauma, fears of intimacy, and anxiety can find themselves unable to perform. Stress, relationship issues, and other factors outside the bedroom can also create performance issues.

That’s why it’s crucial to speak with a healthcare professional before taking medication. ED drugs may not be the solution… or at least not the only solution.

Erectile dysfunction is a common health condition, and there are several erectile dysfunction treatments that all work pretty similarly.

Here’s the gist of how ED medications work:

• The most common erectile dysfunction medications are PDE5 inhibitors. They work to help widen blood vessels in the penis, allowing more blood flow for stronger and longer-lasting erections. Research shows that, when used properly, these ED pills can help improve erectile function.

• Many of these pills work fairly quickly. Sildenafil (Viagra), tadalafil (Cialis), and vardenafil (Levitra) typically start working within 30 to 60 minutes, while avanafil (Stendra) works within 15 to 30 minutes.

• As with most prescription drugs, ED medications can cause side effects. Some of the most common side effects of ED meds include headaches, dizziness, upset stomach, back pain, and nasal congestion.

Still not sure which ED medication is right for you? Talk to a licensed provider to get personalized guidance and erectile dysfunction treatment options, and get back to feeling confident in the bedroom.