Other Tests How should sildenafil (Viagra) be administered? Here you can buy viagra without prescription 50mg viagra online without prescription Erectile dysfunction, or ED, can be a total inability to achieve erection, an inconsistent ability to do so, or a tendency to sustain only brief erections. These variations make defining ED and estimating its incidence difficult. Estimates range from 15 million to 30 million, depending on the definition used. According to the National Ambulatory Medical Care Survey (NAMCS), for every 1,000 men in the United States, 7.7 physician office visits were made for ED in 1985. By 1999, that rate had nearly tripled to 22.3. The increase happened gradually, presumably as treatments such as vacuum devices and injectable drugs became more widely available and discussing erectile function became accepted. Perhaps the most publicized advance was the introduction of the oral drug sildenafil citrate (Viagra) in March 1998. NAMCS data on new drugs show an estimated 2.6 million mentions of Viagra at physician office visits in 1999, and one-third of those mentions occurred during visits for a diagnosis other than ED. Sadeghi-Nejad believes that doctors should screen men for erectile dysfunction. "It's an important quality-of-life issue, and the factors that help prevent cardiovascular disease and diabetes may help decrease erectile dysfunction," he added. Erectile dysfunction. This is one of many types of constricting devices placed at the base of the penis to diminish venous outflow and improve the quality and duration of the erection. This is particularly useful in men who have a venous leak and are only able to obtain partial erections that they are unable to maintain. These constricting devices may be used in conjunction with oral agents, injection therapy, and vacuum devices.