How Long Does Viagra Stay In Your System?

Viagra, also known by its generic name sildenafil, is an oral phosphodiesterase type 5 (PDE5) inhibitor, a medication prescribed to treat erectile dysfunction (ED)

Several factors can influence how long Viagra stays in the system. These are important to consider when assessing the overall safety and impact Viagra treatment may have on a man’s health.

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How does Viagra work?

Viagra treats the symptoms of ED, but it’s not a cure for the condition. 

ED is the persistent inability to achieve and maintain an erection firm enough for satisfactory sexual intercourse. 

For Viagra to work, sexual stimulation is necessary. 

In an erection, a chemical messenger called nitric oxide¹ (NO) is released. NO relaxes the trabecula (specialized muscle/connective tissue fibers) of a particular part of the penis called the corpus cavernosum, thereby maximizing blood flow and penile engorgement.

An erection is, therefore, the result of adequate arterial flow providing sufficient oxygen to the cavernosa and sufficient nitric oxide synthase, which generates nitric oxide.

Detumescence, however, occurs when intracavernosal type 5 cyclic GMP phosphodiesterase (PDE5), an enzyme, breaks down the cyclic GMP. Viagra inhibits PDE5 so that cGMP is not metabolized as quickly, and an erection is sustained longer. 

So, although Viagra doesn’t directly cause an erection, it indirectly slows down the breakdown of biochemicals that help sustain an erection.

Viagra is highly successful. One study² in men with ED found Viagra to have a success rate of 91%.

How long does it take for Viagra to start working?

Viagra is rapidly absorbed and usually works within an hour. Thus it is recommended to be taken an hour before any planned sexual encounter. However, it can start working within 30 minutes or take up to two hours to work for some individuals.

One study found that 71% of participants³ experienced erection onset within 30 minutes. 

Taking Viagra on an empty stomach makes Viagra work faster. Eating a high-fat meal before using Viagra slows its absorption, so it will take longer to start working.

Also, sexual stimulation is needed for Viagra to work. Finding ways to increase sexual arousal before sex, such as foreplay, may help Viagra work faster. 

How long does Viagra stay in the system?

The half-life of Viagra is four hours and is typically considered effective for up to four hours.

For a man who’s sexually stimulated and has sex four hours after taking Viagra, evidence suggests that he will still be able to achieve an erection lasting around 14 minutes. 

Viagra can stay in the system for up to 20 hours, but it takes about four to five half-lives for a drug to be fully eliminated. How long it is effective differs from person to person. FDA labeling states that Viagra is effective for up to four hours, but the effect at four hours is much less than at two hours.

Even though Viagra can work for four hours, the erections typically don’t last this long. Generally, men don’t experience the effects of Viagra after two to three hours, and erections should not be sustained longer than this.

A prolonged erection that lasts for more than four hours is called priapism. This is a medical emergency that can cause permanent damage to the penile tissue. 

Factors that affect how long Viagra stays in the system

Age

Viagra may last longer in people over 65⁴ as their bodies become less efficient at removing drugs. This is because of alterations in proteins in the blood, the main method of how the body transports medication.

Diet and lifestyle

Grapefruit products

When using Viagra, grapefruit and grapefruit products should be avoided. This is because, if Viagra is used, grapefruit slows down the enzymes responsible for part of the breakdown of Viagra in the liver.

Fat intake

High-fat foods slow the absorption of Viagra into the bloodstream. This means it can take longer to have an effect.

Alcohol

A recent meta-analysis⁵ demonstrated that regular consumption of alcohol lowered the risk of erectile dysfunction. However, another study⁶ showed that this might be a J-shaped response that may be harmful in high doses.

However, alcohol and Viagra may have additive effects, particularly through additive effects that may enhance the hypotensive effects of sildenafil; thus, excess alcohol consumption in this context should be avoided.

Medication

Several medications can impact Viagra’s effectiveness. CYP3A4 is one of the main enzymes in the liver that metabolizes numerous medications, chemicals, and any drug that alters its metabolism, either by inhibiting or enhancing it. It can change concentrations of Viagra in the body and cause either lowered effectiveness or increased risk of side effects.

Some examples of CYP3A4 inhibitors include:

Some antibiotics

Certain antibiotics, such as erythromycin and clarithromycin, may increase the levels of Viagra in the bloodstream and inhibit its metabolism, causing it to remain in the system longer. 

Ritonavir

Ritonavir, a drug prescribed for HIV/AIDS treatment, can increase Viagra levels in the bloodstream. These two drugs should not be used together except under extreme circumstances as directed by your doctor.

Since Viagra can stay in the system longer, only a 25-mg dose of Viagra should be used every 48 hours instead of the general recommendation of 50mg every 24 hours. 

Health

Certain medical conditions associated with ED may influence how Viagra works in the body and how long it lasts.

For men with poor liver or kidney functioning, Viagra can stay in the system longer. This is because an impaired liver and/or kidney can negatively impact metabolism and make it more difficult to metabolize drugs such as Viagra out of the body. Your doctor may prescribe lower doses in this context.

Psychological state

For Viagra to help to achieve an erection, sexual arousal is needed. Viagra isn’t effective in men who cannot get sexually aroused due to their psychological state. 

Performance anxiety, fear of sexual failure, low self-esteem, and depression may contribute to a person’s ability to get sexually aroused before having sex. 

How often should Viagra be taken?

Viagra doesn’t have a regular dosing schedule. It should be taken one hour before sex as needed. This means that Viagra isn’t required when the man isn’t struggling to achieve an erection.

It’s generally safe to take one dose of Viagra daily, and many men can take it for an extended time.

However, this doesn’t apply to everyone, so men should always check with their healthcare provider to ensure a safe dosage based on their medical history. For some men, such as those taking ritonavir, it’s safer to take Viagra less often — once every two days, for example, or look for alternative medications as guided by their physician.

Viagra should not be taken more than once in 24 hours. Even though the effects seem to have subsided after a few hours, it’s still in the system in small amounts, so taking it again too soon can be dangerous. 

How much Viagra should be taken?

The amount of Viagra men can take depends on their age and medical history. Men should always follow the advice of their doctor when using Viagra. 

Viagra is available in 25mg, 50mg, and 100mg. 

The standard dose is 50mg. This is safe and effective for most men. However, if the Viagra isn’t working at that dosage and no adverse side effects are present, the dose may be increased to 100mg. 

Alternatively, if side effects occur, even if minor, taking a lower dose of 25mg may be safer. Additionally, men with liver or kidney problems, those older than 65, and those on certain medications are advised to take this lower dose. 

It’s important to take Viagra at the correct dose. If the dose is too high, it increases the chance of experiencing severe side effects, including priapism. Viagra also lowers blood pressure, so high doses may develop dangerously low blood pressure. 

What can be done to ensure that Viagra is metabolized properly?

  • Use a lower dose, such as 25mg rather than 50mg or 100mg.

  • Avoid certain medications, such as CYP3A4 inhibitors. 

Can men who have a drinking problem take Viagra?

Currently, little research on the combination of Viagra and alcohol is available. One study⁷ found that 63% of participants used alcohol alongside the generic form of Viagra. It appears that, in general, it’s safe to use Viagra while drinking alcohol casually. 

However, it may not be a good idea for men with drinking problems to take Viagra.

First, alcohol and Viagra both reduce blood pressure. Using both of these substances, especially when consuming excessive amounts of alcohol, the person’s blood pressure may drop to dangerously low levels.

Heavy drinking is also a risk factor for ED. It may make it harder to get an erection even when not taking Viagra.

One study⁸ in men with ED found that those who used alcohol alongside PDE5 inhibitors such as Viagra experienced more adverse effects, such as headaches and facial flushing. Alcohol abuse may also lead to more serious complications, such as chest discomfort and dizziness when used in combination with Viagra. 

Researchers⁹ also think that excessive alcohol use with Viagra could be associated with the onset of coronary disease or systemic hemodynamic instability. 

What are the long-term effects of taking Viagra?

Most side effects of Viagra are temporary and only mild to moderate in severity. Generally, Viagra is safe for long-term use. 

However, some long-term side effects, though rare, can occur and should be kept in mind.

Long-term vision loss

Viagra can lead to a sudden loss of vision in one or both eyes. This could be a permanent condition called non-arteritic anterior ischemic optic neuropathy.¹⁰ Anyone who experiences vision loss should stop using Viagra and consult a healthcare professional.

Long-term hearing loss

Viagra can cause hearing loss, which is sometimes permanent. This hearing loss is usually one-sided and occurs within 24 hours of drug administration though no causal relationship has been demonstrated.

Anyone who experiences hearing loss should stop using Viagra and seek medical attention as soon as possible. 

Prolonged erection and penile damage

In some cases, Viagra can cause priapism, which, as mentioned earlier, is a prolonged erection lasting longer than four to six hours. This is a serious condition and can lead to permanent penile damage and permanent ED.

Dependency and the risks of recreational use

Viagra has not been associated with any risk of physical dependency.

However, evidence suggests that ED medications such as Viagra are more frequently associated with decreased erectile confidence. This, in turn, is associated with reduced erectile function.

Some men use ED medications for recreational purposes, such as to improve their sexual performance, rather than directly using them for their intended purpose — to treat ED.

Men who use ED medications for recreational purposes are at greater risk of becoming psychologically dependent, which could lead to psychogenic-based ED symptoms.

When to see a doctor

Men concerned about erectile function should see a doctor as soon as possible. ED can be caused by various underlying medical conditions and lifestyle factors (like diabetes, high blood pressure, being overweight, and depression), so it’s important to bring these under control when addressing ED. 

Viagra is a prescription medication, so it can’t be used until after visiting a doctor and having been prescribed. Various factors may influence whether Viagra will be safe and effective for any individual, so the doctor should be aware of any underlying medical conditions, allergies, and other medications currently being taken. 

Once Viagra treatment has begun, the man should monitor his condition to detect negative side effects. If any adverse effects appear, or if the Viagra isn’t working, seeing a doctor again to have the dose reviewed is a good idea. 

Successful ED treatments alternative to Viagra are also available, so if Viagra doesn’t seem effective or safe, other ways of achieving erections can be found to help with a satisfactory sexual relationship. 

The lowdown

Viagra is a safe and effective treatment for ED. It has a rapid onset of action and can help men achieve erections for hours after taking it. Several factors can influence how effective Viagra is and how long it stays in the system.

  1. The use of vasoactive drugs in the treatment of male erectile dysfunction: Current concepts (2020)

  2. Oral sildenafil (Viagra™) in male erectile dysfunction: Use, efficacy and safety profile in an unselected cohort presenting to a British district general hospital. (2002)

  3. Onset and duration of action of sildenafil for the treatment of erectile dysfunction (2002)

  4. Label: VIAGRA (sildenafil citrate) tablets | Access Data

  5. Alcohol consumption and erectile dysfunction: Meta-analysis of population-based studies (2007)

  6. A meta-analysis of erectile dysfunction and alcohol consumption (2021)

  7. The weekend drug; Recreational use of sildenafil citrate and concomitant factors: A cross-sectional study (2021)

  8. Influence of alcohol on phosphodiesterase 5 inhibitors use in middle- to old-aged men: A comparative study of adverse events (2019)

  9. PDE5 inhibitor sildenafil attenuates cardiac microRNA 214 upregulation and pro-apoptotic signaling after chronic alcohol ingestion in mice (2020)

  10. Viagra® (sildenafil citrate) tablets, for oral use | Access Data

Other sources:

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