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Sildenafil for Erectile Dysfunction (ED) | Comprehensive Guide

Sildenafil for Erectile Dysfunction (ED) | Comprehensive Guide
Dr. Constance Odom, MD Picture of Dr. Constance Odom, MD

Medically reviewed by

Written by our editorial team.

Last Edited 8 min read

Though it can feel like the most isolating condition in the world, erectile dysfunction is far from uncommon. In fact, mild to moderate symptoms affect 10% of men, growing with every decade of life they live. That means by age 50, males have a 50% chance of experiencing it.

For the past 20 years, a little blue pill has helped make things better.

Sildenafil, better known as Viagra, is the prescription drug that most men turn to when they start experiencing symptoms of erectile dysfunction. From commercial spots to celebrity endorsements, there has been no shortage of media coverage around this drug.

Yet, how much do you really know about it? If you're considering taking Sildenafil to help curb symptoms of your erectile dysfunction, read on. Today, we're covering the ins and outs of the medication including its history, composition and how to take it.

Reay to learn more? Let's get started.

What is Sildenafil?

Sildenafil is a prescription medication used to treat impotence or erectile dysfunction in men. It was first studied by British researchers in the 1980s as a treatment for hypertension or high blood pressure.

It failed to fully achieve the level of success expected in this realm. Yet, chemists did discover that all was not lost. One routine blood pressure check revealed that the men participating in the study all experienced erections. Thus, before biopharmaceutical company Pfizer shelved the medication entirely, they examined this avenue further.

On March 27, 1998, the U.S. Federal Drug Administration (FDA) formally approved Sildenafil as a treatment for erectile dysfunction. It was the first oral medication slated for this use. Branded as Viagra, it went on to become the most popular and well-known drug of its kind.

How Does Sildenafil Work?

Put simply, Sildenafil improves blood flow to the penis. At least two-thirds of men report experiencing improved and longer-lasting erections after taking the drug.

In some cases, sildenafil is used in its originally intended form, to treat hypertension in both males and females. Yet, it is more commonly known for the aforementioned use.

The Role of PDE5 Inhibitors

Sildenafil belongs to a class of medications known as phosphodiesterase 5 (PDE5) inhibitors.

When a man is sexually stimulated, his nerve endings work alongside endothelial cells located in his penis to release Nitric Oxide (NO). In response to this signal, an enzyme known as guanylate cyclase acts to convert guanosine triphosphate (GTP) into cyclic guanosine monophosphate, or cGMP.

This cGMP messenger molecule causes smooth muscle tissues to relax, which allows blood to flow to that particular area, leading to an erection. When the erection is over, phosphodiesterase type 5 (PDE5) works to convert cGMP back to its inactive state of guanosine monophosphate (GMP).

Men who experience erectile dysfunction do not produce enough NO to jumpstart this process in the first place. Thus, as soon as they begin to produce cGMP, their body is already working to convert it back to GMP, preventing a full erection. To this end, Sildenafil works by inhibiting PDE5, occupying its active site instead.

This slows the hydrolyzation of cGMP and encourages the smooth muscle to relax, allowing blood flow and erection. The muscles in both the lungs and the penis are similar, allowing Sildenafil to encourage blood flow in both areas, treating both hypertension and erectile dysfunction.

Taking Sildenafil for ED

If you're reading this, you're likely interested in understanding how to begin taking Sildenafil for ED. There are several precautions to take and key facts to understand, so let's break it down to the basics.

In some cases, erectile dysfunction can be treated with simple lifestyle changes. Some men find that after losing weight, ceasing to smoke, reducing their alcohol intake, or eliminating certain stressors they are able to achieve more fulfilling erections.

Yet, there are others who rely on medications such as Sildenafil to help them get the maximum physical and emotional pleasure they can during sex.

Who Can Take It?

Sildenafil for erectile dysfunction is recommended for men, ages 18 and older. When prescribed as a treatment for ED, it is not for women or children.

Who Should Not Take It?

Most healthy men can take the drug without any notable side effects. Yet, speak to your doctor before beginning this regimen if you've experienced any of the following conditions:

  • A penis deformity, including Peyronie's Disease

  • Sickle cell anemia (abnormal red blood cells)

  • Leukemia (cancer of blood-forming tissues)

  • A heart condition that would render the organ too strained during sex

  • Stomach ulcer

  • Low blood pressure

  • Uncontrolled high blood pressure

  • Deformed penis

  • Pulmonary hypertension

  • Multiple myelomas (cancer of plasma cells)

  • A bleeding condition such as hemophilia

  • An allergic reaction to Sildenafil in the past

  • Serious heart or liver issues

  • Stroke

  • Heart attack

  • A rare, genetic eye disease, including retinitis pigmentosa

It is still recommended that you speak to your doctor about your concerns to see if there might be another treatment route available. Yet, those who have experienced or are experiencing the above conditions should not take Sildenafil for ED.

A Caution on Nitrates and Other Medications

Anyone taking nitrates for chest pain should also avoid Sildenafil. This is because those medications are designed to increase the flow of both blood and oxygen to your heart. As they dilate your arteries and veins, they enable your heart to pump more effectively, which can help relieve your discomfort.

When nitrates are taken alongside Sildenafil, the combination can result in dangerously low blood pressure. If you're on medication for chest pain and aren't sure if it's classified as a nitrate, be sure to ask your doctor before beginning any other medications.

For the same reason, you should also avoid the medication if you're currently taking guanylate cyclase stimulators for pulmonary hypertension. A common drug in this category is Adempas or riociguat.

How Do You Take It?

It seems simple enough to take a pill and engage in sexual intercourse. However, it's important to understand the timeline of Sildenafil to reap its maximum benefits.

You can take the drug for up to four hours before you intend to engage in sex. In most cases, it starts working within 30 to 60 minutes.

You'll take the drug with a glass of water or juice, though you should avoid taking it with grapefruit juice. This fruit can increase the levels of medication in your blood, leading to a host of complications from headaches to low blood pressure.

One common misconception is that taking the pill on its own will work as a magic "stimulation" tool that will ultimately lead to an erection. However, for the medication to work, it must be used in conjunction with stimulation and arousal.

Sildenafil is available in a few different strength levels depending on your need. The smallest dosage available is 25mg and the strongest one is 100mg. Most men will be prescribed a 50mg dose of the medication, to be taken on an as-needed basis that should not exceed two times per day. There are also single-dosage packets available that your doctor can prescribe in 50mg and 100mg amounts.

Once you've been on the medication for a while and can report back to your doctor on its performance, your dose might be increased or decreased depending on how it's been working so far.

What Happens Immediately After Taking It?

Sildenafil has a rapid onset, meaning it takes action as soon as you ingest it, though you don't feel the effects until a little later. If you take it in a fasted state, or on an empty stomach, you can expect to achieve peak plasma concentrations around the 30 to 60-minute timeline.

If you take the medication with a high-fat meal, on the other hand, you will likely have to wait a little longer. This slows how quickly the drug is absorbed into your bloodstream. The same holds true for taking it with alcohol, which can also slow the process. So, hold off on the cheeseburger, french fries, and beer and opt for a healthy and nutritious meal instead.

Once you've had sex, the erection should go away.

What If It Isn't Working?

When taken as recommended, you should experience an erection between 30 and 60 minutes after taking Sildenafil. If you are not achieving one within the desired timeframe, or your erections aren't as hard as you'd like them to be, there are a few reasons why this might be the case.

First, you may be attempting to have sex too soon after taking the drug. Or, you might have waited too long. It's important to follow the recommended guidelines on when to take it and how.

You might also need to speak with your doctor about upping your dosage to a higher, more potent level, as yours might be too low to take effect. Lastly, you might need to achieve a higher level of arousal to see peak performance.

Are There Any Side Effects to Note?

There are three different ways to classify a medication's side effects including those that occur as a result of an overdose, common/mild ones, and serious ones.

Overdose Side Effects

If you take too much Sildenafil, you may experience overdose symptoms. Contact your doctor immediately if this occurs. Symptoms to look out for include:

  • Headache

  • Upset stomach

  • Dizziness

  • Blurred vision

  • Nasal blockage

Men who take too much Sildenafil may also experience priapism. This is an erection that lasts more than four hours and can permanently damage penile tissues

Common Mild Side Effects

While you're on the medication and taking it as recommended, you may still experience some adverse side effects. Common but mild ones are similar to those that occur as a result of an overdose. They include:

  • Headache

  • Body aches

  • Hot flushes, especially in the face

  • Indigestion and upset stomach

  • Blurred vision/vision discoloration

  • Stuffy nose

  • Dizziness

You can keep taking the medication if these occur, but contact your doctor about them and monitor them to ensure they subside.

Serious Side Effects and Allergic Reactions

Though they are rarer, some serious side effects have been known to occur to some people taking Sildenafil for erectile dysfunction. These usually affect only around one in 1,000 people and include such symptoms as:

  • Chest pain

  • Priapism

  • Vision loss

  • Hearing loss

  • Abnormal and acute skin reaction including blisters, rash, and swelling

  • Fever

When these occur, you should stop taking the medication and contact your doctor right away. It is also possible (though rare) to have an allergic reaction to Sildenafil which can lead to anaphylactic shock. If you begin wheezing, coughing, have trouble breathing or find it difficult to talk after taking the drug, contact emergency personnel right away.

Learn More about Your Health Today

Especially as we age, it's critical that both men and women take control of their health and proactively treat and control any issues they can.

From getting your erectile dysfunction under control with Sildenafil to learning more about managing your weight, hormone replacement, and life-changing medications, there is no shortage of information to digest in this arena.

That's where we come in.

We've pared down the slew of health-related data available to give you just the knowledge you're looking for. Since 2004, we've provided both on-site consultations as well as telemedicine meetings to help patients get the most from our health programs, which include anti-aging, weight-loss, and wellness focus areas.

We'll give you the exercise tips, nutritious recipes, program information, drug information and general wellness advice you need to look and feel your best.

Get in touch today to ask us questions, learn more and connect with like-minded enthusiasts. We'll help you take control of your health like your life depends on it -- because it does.

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 physician about the risks and benefits of any treatment. Nu Image Medical may not offer the medications or services mentioned in this article.