How Long Does Viagra Last?

Viagra (sildenafil) is an oral drug used to treat erectile dysfunction (ED) that starts working within one hour and can last for around four hours. It was the first drug approved for the use of ED, a condition that affects roughly one in four males in the United States.

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

How Long Viagra Lasts

Viagra usually lasts for around four hours, although the effect may be longer lasting in some people. There are several possible reasons for this:

• Drugs known as pharmacokinetic enhancers boost the level of other 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. Severe liver disease can slow this process and maintain Viagra in the bloodstream for longer periods.
• Older age tends to prolong the effects of Viagra as metabolism generally slows with age.
  

How Long It Takes 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.

How Long It Stays in Your System

Viagra has a drug half-life of four hours. This means that the level of sildenafil in your bloodstream will drop by 50% within four hours. This is typically the level by which the drug is no longer bioactive (able to exert a physiological effect).

While Viagra will probably not keep you erect after you ejaculate, it may help decrease the refractory period. This is the time after ejaculation when you have difficulty getting an erection again. In younger males, the refractory period may be as short as a few minutes and as long as a few hours or days in older males.

How Viagra Works

An erection occurs when a series of chemical processes triggered by sexual arousal or the manual stimulation of the penis causes the penis to engorge with blood.

ED occurs when parts of the system that contribute to erections fail. This includes changes in blood vessels that deliver blood to the penis, which can narrow and harden with age.

Viagra works by preventing the breakdown of an enzyme called cyclic guanosine monophosphate (cGMP) that causes the widening of blood vessels, referred to as vasodilation. By increasing the amount of cGMP in the bloodstream, blood flow to the penis is increased, better enabling an erection.

What Happens if It Doesn't Work?

It is important to note that Viagra will not work in the absence of sexual stimulation or interest. If you have a low libido (sex drive), taking more Viagra will do nothing to enable an erection but will only serve to increase your risk of side effects.

If you take Viagra and find that it doesn't work after an hour, it may be due to improper or inadequate dosing. While Viagra is commonly dosed at 50 milligrams (mg), some people may need as much as 100 mg to achieve an erection.

Even so, do not double up the Viagra dose without speaking with your healthcare provider.

Eating a high-fat meal can also blunt Viagra's effects. Not only does it increase the time it takes for the drug to work, but it also decreases the concentration of Viagra in the bloodstream by around 29%.

If you take Viagra and it doesn't work at all, it could be due to any number of other reasons, including:

• A penile injury, including Peyronie's disease
• Atherosclerotic heart disease, which can reduce blood flow to the penis
• Neurologic damage caused by prostate surgery, diabetes, or stroke
• Neurologic conditions like multiple sclerosis or Parkinson's disease
• Psychological issues, like performance anxiety or relationship problems

Other treatments may be needed to help overcome these issues.

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.

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.

Interactions

Viagra can interact with many medications, in some cases exaggerating the vasodilating effects of the accompanying drugs. When this happens, you might experience a steep drop in blood pressure, causing flushing, headache, dizziness, and, in severe cases, fainting.

These include drugs like:

• Nitrates like nitroglycerin used to treat angina
• Alpha blockers like Flomax (tamsulosin) and Uroxatral (alfuzosin) used in males with an enlarged prostate
• High blood pressure medications like calcium channel blockers, ACE inhibitors, angiotensin receptor blockers (ARBs), and diuretics ("water pills")

Some of these interactions are minor and may only require a dose adjustment or a separation of doses by several hours. At other times, the interaction may be major and require the avoidance of Viagra and other PDE-5 inhibitors.

Alcohol can also be problematic. As a depressant, it 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.

Alternative Treatments

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

Among them:

• Levitra (vardenafil) can last for around five to seven hours, slightly longer than Viagra.
• Cialis (tadalafil) can last up to 36 hours in some people.
• Stendra (avanafil) is faster-acting than the other PDE-5 inhibitors, enabling erections in as little as 15 minutes, and can last for up to six hours.

Other medical options include penile pumps, penile implants, psychotherapy, and alprostadil injections.

Several alternative therapies are thought to improve ED, although the evidence supporting their use is generally weak. These include:

• L-arginine
• Ginseng (Panax ginseng)
• Pycnogenol (Pinus pinaster bark tree extract)
• Horny goatweed (Tribulus terrestris)
• Yohimbe
• Deydroepiandrosterone (DHEA)
• Acupuncture

Weight loss can also help if you have overweight or obesity. Stress reduction techniques like meditation or breathing exercises may also help if you experience performance anxiety.

And, quitting cigarettes is the single most important lifestyle change to make if you struggle with ED. Doing so can improve your ability to achieve erections by as much as 25% according to a 2023 study in Sexual Medicine Review.

When to See a Healthcare Provider

Today, many people get their Viagra through online sites that connect them with a telehealth provider who prescribes the drug based on an often cursory set of questions. While this may be safe for some people, it may not be so for people with uncontrolled hypertension (high blood pressure) or severe heart disease.

In such cases, it is important to meet with a healthcare provider to understand the benefits and risks of treatment. This includes a specialist in the male reproductive tract known as a urologist.

You should also speak with a urologist if Viagra doesn't help you achieve and sustain an erection suitable for sex. A battery of tests, including psychological evaluations, can be performed to narrow the possible causes and dispense the appropriate treatment.

Summary

Viagra is a PDE-5 inhibitor 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.