How Long Does Viagra (Sildenafil) Last? (2024)

Viagra (sildenafil) is an oral drug used to treat erectile dysfunction (ED). Viagra can last for about four hours or more in some people and should be taken 30 minutes to an hour before sexual activity.

ED affects around one in four people with penises in the United States—or roughly 30 million people—with the incidence increasing to one in three after the age of 55.

Viagra belongs to a class of drugs called PDE-5 inhibitors that help stimulate the dilation (widening) of blood vessels in the penis, allowing it to engorge more fully with blood to achieve and sustain an erection suitable for sex.

This article explains how Viagra works, how long the effects last, and the various factors that affect how effectively the drug works.

How Does Viagra Work?

An erection occurs when a series of chemical processes (triggered by sexual arousal or the manual stimulation of the penis) cause the engorgement of the penis with blood. Erectile dysfunction occurs when parts of the system that contribute to erections (including nerves and vascular valves) fail, often in tandem with advancing age.

Viagra contains the active ingredient sildenafil. The drug works by preventing the breakdown of an enzyme called cyclic guanosine monophosphate (cGMP) that regulates vasodilation (the widening of blood vessels). By making more cGMP available, blood flow can be increased to the penis, enabling an erection.

How Long Does Viagra Take to Start Working?

Viagra takes about an hour to work, although some males are able to achieve an erection within 30 minutes of a dose.

Viagra reaches its maximum concentration in the bloodstream within one to two hours. This is the time frame during which Viagra exerts its optimal effects. After two to three hours, the effects start to diminish.

Viagra does not work in the absence of sexual stimulation or interest. You need to be sexually aroused in order to reap the benefits of treatment. For best results, take Viagra one hour before sexual activity or foreplay but no longer than four hours beforehand.

How Long Does Viagra Last?

Viagra usually lasts for around four hours, although the effect may be longer lasting in some people. Even so, try not to take Viagra more than four hours before sexual activity just to be safe.

There are several reasons why Viagra may be longer lasting in some people:

• Certain drugs are pharmaco*kinetic enhancers that boost the level of certain drugs in the bloodstream. An example is the HIV drugs cobicistat and ritonavir which can prolong the effects of Viagra for up to 24 hours.
• The liver is tasked with breaking down Viagra and removing it from the system. Underlying liver disease can slow this process and maintain Viagra in the bloodstream for longer periods.
• Older age tends to prolong the effects of Viagra insofar as metabolism generally slows the older you get.

Will Viagra Keep Me Erect After I ejacul*te?

While Viagra will probably not keep you erect after you ejacul*te, it may help decrease the refractory period. This is the time after ejacul*tion when you have difficulty getting an erection again.

The refractory period may be as short as a few minutes in younger people and as long as a few hours or days in older adults.

How Long Does It Take for Viagra to Leave the System?

Viagra has a drug half-life of four hours. This means that 50% of the drug will be cleared from your system after four hours. Thereafter, the concentration of the drug will continue to drop by half every few hours until no drug is left in the system—usually within 16 to 24 hours.

This does not mean that Viagra will work for 16 to 20 hours. While there may still be some drug left in your bloodstream, the amount will not be bioactive (able to exert a biological or physiological response).

Factors That Negatively Affect Viagra

There are certain factors that can affect how well Viagra is absorbed into the bloodstream. The drop in drug concentration can reduce its ability to work effectively.

These factors include:

• High-fat meals: Taking Viagra with a high-fat meal not only increases the time it takes for the drug to work but also decreases the concentration of Viagra in the bloodstream by 29%.
• Alcohol: As a depressant, alcohol slows blood circulation and the distribution of the drug throughout the body. This not only counteracts Viagra's effects but can also worsen ED over the long term if alcohol is consumed in excess.
• Age and general health: Viagra can help anyone with ED, but it tends to be most effective in younger males and less so in older males with multiple chronic health condtions that affect blood circulation (like kidney disease or diabetes).

Viagra Side Effects

As with all drugs, Viagra can cause side effects. The side effects tend to be relatively mild, although some people may experience them more profoundly than others.

Common side effects of Viagra include:

• Headache
• Flushing
• Stuffy nose
• Indigestion
• Dizziness
• Nausea
• Blueish vision

An uncommon but potentially serious side effect is priapism in which an erection lasts six hours or more, causing pain and potentially long-term tissue damage. Priapism is considered a medical emergency in need of immediate treatment.

Viagra and ejacul*tion

The effects of Viagra on ejacul*tion are unclear. One study has shown that Viagra may improve premature ejacul*tion, meaning you will last longer during sex. With that said, it is unclear if the improvement is due to Viagra or the fact that the drug reduces performance anxiety which contributes to premature ejacul*tion.

Alternatives to Viagra

PDE-5 inhibitors are the most common drugs used to treat erectile dysfunction. Viagra was the first PDE-5 inhibitor introduced in 1998, but there are others you can turn to.

Among them:

• Levitra (vardenafil) is similar to Viagra and may last up to five hours.
• Cialis (tadalafil) is a longer-lasting PDE-5 inhibitor that enables erections up to 36 hours after a dose. It can also be taken daily or as needed.
• Stendra (avanafil) is faster-acting than the other PDE-5 inhibitors and has relatively milder side effects.

Other treatments that can help with ED include penile pumps, penile implants, psychotherapy, and alprostadil injections.

Summary

Viagra is a PDE-5 inhibitor taken by mouth that can help you get an erection if you have erectile dysfunction. It tends to work within one hour and lasts for up to four. Taking Viagra with alcohol or a high-fat meal can reduce its effectiveness.

Common side effects include headache, flushing, indigestion, blue vision, and stuffy nose.