How Long Does Viagra Last?

Other Considerations

A number of things can potentially shorten or extend the duration of Viagra’s effect. Taking the drug after a large meal, especially one with high fat content, can delay its absorption into the bloodstream. This can extend both the time it takes for the drug to take effect and its duration of action after ingestion. Conversely, taking Viagra on an empty stomach can lead to faster onset of effectiveness but a shorter duration of action. The effect of Viagra may last longer in men older than 65 and in those with significant kidney or liver disease due to a reduced rate of clearance of the drug from the body. Certain prescription medications can also increase or decrease the rate of Viagra clearance from the body, thereby altering how long the drug remains effective.

Priapism is a rare but serious side effect of Viagra and other prescription ED medicines. Priapism refers to a persistent, painful erection that continues despite lack of sexual stimulation. This condition requires immediate medical care as it can lead to lasting damage to the penis. Seek emergency medical care if you experience an erection lasting more than 4 hours.

Typical Onset and Duration of Action

Viagra, the trade name for the drug sildenafil, was the first erectile dysfunction medication approved for use in the United States in 1998. Although other ED drugs are now available, Viagra remains a popular choice. The drug is considered a short-acting ED medication. Viagra usually takes effect within 30 minutes, although there may be a delay if the drug is taken on a full stomach. It typically remains effective for approximately 4 to 5 hours. However, the effects may begin to diminish after 2 hours as manifested by less firmness of the penis or a shorter duration of an erection. These time frames come from multiple studies and reflect typical user experiences. However, at least one study suggests that Viagra may remain effective for up to 8 to 12 hours in some men.

Extended Effectiveness

Early studies of Viagra focused on determining the effectiveness of the drug when used as directed, meaning when taken approximately 60 minutes before sexual activity. The primary outcome measured in most of these studies was achieving an erection sufficient to engage in successful intercourse. Later studies examined how long the drug remained effective. These studies were based knowledge that blood level of the drug typically drops to half of its peak level within 4 hours. Therefore, these studies typically stopped measuring effectiveness after 4 hours.

However, a study published in September 2004 in the “Journal of Sexual Medicine” tested effectiveness at up to 12 hours after ingesting sildenafil. The researchers found that among men who responded to the drug at 1 hour, 82 percent also achieved a firm erection 8 hours after administration in response to visual sexual stimulation. At 12 hours, 45 percent of these men continued to exhibit a response to the drug. However, the duration of the erections tended to decrease at these later time points. The results of this study support the notion that the duration of action of Viagra may be significantly longer than 4 hours in some men.

Reviewed and revised by: Tina M. St. John, M.D.