Sildenafil: Ultimate Guide

April 27, 2021

4 mins

Men of all ages are likely to experience erectile dysfunction at some point in their lives, often as a result of stress, exhaustion, or anxiety. However, when it becomes a chronic issue it may be a sign of a more serious underlying condition. 

Erectile dysfunction is estimated to affect nearly 30 million American men. One of the most well-known treatments for erectile dysfunction is Viagra®. Here’s what you need to know. 

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What is Sildenafil? 

Sildenafil is a prescription drug that mostly comes in the form of a tablet but can be a liquid or even an injection. The most popular form of sildenafil is Viagra®. It's also available under the brand name Revatio. Both medications are manufactured by Pfizer. 

In the last few years, other pharmaceutical companies have begun to legally manufacture sildenafil so it is much more easily available than it has been in years past. These generic versions will often cost much less than the brand names with virtually identical chemical compositions and effectiveness. 

What is Sildenafil Used For? 

Sildenafil is used to treat erectile dysfunction and heart conditions like pulmonary arterial hypertension.

Viagra® is made up of sildenafil and is legally only allowed to treat erectile dysfunction. Viagra pills come in doses of 25mg, 50 mg, or 100 mg. It's recommended to take the medication right before engaging in sexual activity.

Revatio is another drug that is composed primarily of sildenafil but is used to treat pulmonary arterial hypertension. People with this condition have elevated blood pressure levels in the lungs. Revatio can be consumed as tablets or as a liquid in 20 mg doses. However, they are usually prescribed to be taken three times a day, every day for as long as necessary.

How Does Sildenafil Work? 

Sildenafil belongs to a class of drugs that is known as phosphodiesterase type 5 (PDE5) inhibitors. These inhibitors work to block PDE5 which is an enzyme located in the walls of blood vessels. By blocking PDE5 these blood vessels can relax and improve blood flow throughout the body.

Depending on which condition is being treated, sildenafil will work in different ways. 

• When treating erectile dysfunction, sildenafil will help to increase the blood flow to the penis. This will help to achieve or maintain an erection, but will only work in the event of arousal. Simply taking the pill will not be enough to achieve an erection. 

• When sildenafil is being used to treat pulmonary arterial hypertension, it helps to relax the muscles of the lungs and open up their blood vessels. This will help to decrease the built-up blood pressure in the lungs. Sildenafil helps to slow down the progression of this illness and also helps to make exercising easier.

How Quickly Does It Work? 

Sildenafil will typically stay in your system for about three to five hours after taking it, but the effects may take around 30 minutes to kick in. The maximum effectiveness will typically peak around an hour or so after ingesting, but this could be influenced by other factors.

Tips For Using Sildenafil 

The following are some examples of how to maximize the effectiveness while using sildenafil:

Eat multiple small meals

For best results, don’t eat before using sildenafil, but if you must eat then make it a light meal. Eating a large, heavy, or high-fat meal before taking it will delay its absorption which means it will take longer to take effect. In addition, these heavier and fatty meals will divert blood to the digestive system which will take away from the potency of the erection.

Practice patience

It will take around 30 minutes or so before the effects start to kick in, so be patient. Some people seem to think that as soon as the pill is popped then the sexual activity can start right away but it will take time to work through your system. 

It will last a few hours so no need to rush, and taking more than the typical dose won’t speed up the process and could cause some issues with the erection not going away after sexual activities have concluded. 

Avoid drinking alcohol

One or two drinks won’t matter too much but drinking a lot can after taking sildenafil can ruin the night. In general, moderate to heavy drinking can hurt erectile functions but when coupled with medication it may cause a significant drop in blood pressure. 

Set the mood

Contrary to what some people may think, Viagra® will not work without being aroused first. Sildenafil uses nitric oxide, a chemical released during arousal to help the body reach arousal.

A History Of Sildenafil 

In 1989, two British scientists employed by the pharmaceutical manufacturer Pfizer were working on a potential treatment for hypertension (high blood pressure) and angina (chest pain due to reduced blood flow to the heart). Sildenafil was patented in 1991 and when early trials began, the results were largely disappointing as it was not a very effective treatment for either. 

However, it soon became apparent that patients were experiencing a significant increase in the amount of erections they were reporting as a side effect. Although these results were not expected, the increase in blood flow through the arteries prompted sexual arousal.

Soon the research shifted toward slidenafil being a treatment for erectile dysfunction and the drug was eventually approved by the Food and Drug Administration (FDA) in 1998.  

Despite the rise of potential rivals like tadalafil (Cialis®) and vardenafil (Levitra), Viagra® stayed on top of the market for treating erectile dysfunction. In 2013, Pfizer’s 15-year patent on Viagra® in the United Kingdom expired. 

Since then, there have been many new options for sildenafil on the market.

What Are the Side Effects of Sildenafil? 

Sildenafil is largely considered to be a fairly safe drug, barring specific conditions, with limited side effects. The most common are usually headaches, indigestion, and flushing of the face or body but even these are largely uncommon. 

Potential side effects of sildenafil may include:

• Nosebleeds

• Headaches

• Indigestion

• Flushing

• Trouble sleeping

• Diarrhea

• Fever

• Respiratory infection

• Nausea

• Vomiting

• Bronchitis

Interactions with Other Medications

The most important thing about sildenafil is not mixing it with the wrong medications. While the above side effects will typically be an inconvenience, these symptoms could result in severe consequences. To avoid interactions, it’s important that your doctor knows all of the medications you are currently taking and what they are treating. 

If you take any of the following drugs then you generally should not take sildenafil:

• Nitrate

• Guanylate cyclase stimulators

• HIV drugs

• Certain antibiotics

• Certain antifungals

• Alpha-blockers

• Blood pressure drugs

• Avanafil

• Tadalafil

• Vardenafil

In addition, certain medical conditions could make taking sildenafil potentially dangerous. 

If you meet any of the following criteria then you should generally avoid sildenafil and other erectile dysfunction drugs as well:

• If you are over the age of 65

• Have a heart condition or arrhythmia

• A history of pulmonary veno-occlusive disease

• Have Peyronie’s disease

• A history of stomach ulcers or bleeding

• Have sickle cell anemia

The Takeaway

Sildenafil is a drug created to treat erectile dysfunction and pulmonary arterial hypertension. Arguably the most popular treatment for erectile dysfunction, Viagra® is composed primarily of sildenafil. 

For over a decade, Pfizer owned the patent on sildenafil and Viagra®. However, in the years since those patents have expired, there have been lots of different companies making their own erectile dysfunction treatments from sildenafil. Viagra® is more expensive than generic versions of sildenafil with similar effectiveness.