Viagra Every Night or Just As Needed?               

They are called the "neurovascular bundles of Walsh," and they are the tiny, very fragile bundles of nerves that are responsible for erection. "Ever since Patrick Walsh’s discovery of these bundles and his subsequent demonstration of how to spare them during radical prostatectomy, there has been hope for men wishing to regain potency after surgery," says urologist Christian Pavlovich, M.D. "However, even with meticulous nervesparing technique, there are still some men whose erectile function does not recover fully after radical prostatectomy." Viagra and similar drugs, known as "phosphodiesterase- 5 inhibitors," have helped many men to achieve better erectile function after surgery. But doctors have debated the best way for men to use these drugs: Would it be more helpful for recovery of erectile function for a man to take one of these medications every day, or just as needed?

Two studies of short-acting drugs in this category, Viagra and Levitra, showed conflicting results. One randomized trial found that "nightly Viagra use was beneficial compared to placebo, while a larger trial found that Levitra was most effective when taken on demand, rather than nightly," says Pavlovich. "Nevertheless, many urologists still prescribe taking these drugs nightly after radical prostatectomy, which raises the expense and also increases the potential side effects in men who are recovering from major surgery."

Recently, Pavlovich, Bruce Trock, Ph.D., and colleagues at the Brady decided to address this issue in a study of radical prostatectomy patients under age 65, with good erectile function and supportive sexual partners. They randomly assigned 100 of these men to either nightly or on-demand Viagra (50 mg) for a year after their surgery, followed by one month of taking no medication. "Assessments of erectile function and urinary function were performed during this time, and neither the men nor the physicians knew which group the men had been assigned to," notes Pavlovich. "Placebo pills were given to match the study drug every night or on-demand."

The investigators made several important findings: "First, this study provided more evidence that taking short-acting drugs like Viagra and Levitra every night does not confer any advantages compared to taking them on-demand after radical prostatectomy," Pavlovich says. In fact, erectile function turned out to be similar or better in men who took Viagra as needed, compared to men who took it every night. "We also found that the recovery of both erectile function and urinary function after radical prostatectomy was very much improved by better degrees of nervesparing. We also discovered, to our surprise, that urinary quality of life was adversely affected by nightly doses of Viagra in the first months after radical prostatectomy."


"Erectile function after nervesparing
radical prostatectomy
turned out to be similar or better
in men who took Viagra as
needed, compared to men who
took Viagra every night."

What about long-acting phosphodiesterase- 5 inhibitors, drugs such as Cialis? These are currently being evaluated in comparable trials, Pavlovich reports. "However, the enthusiasm for daily Cialis use after radical prostatectomy must be tempered by the lack of published data supporting it at this time, by the relaxing effect that Cialis is known to have on lower urinary tract symptoms," which might delay the recovery of urinary continence, "and by the lack of improvement with nightly – compared to on-demand – use of Viagra and Levitra in these studies. Ultimately, it appears that sparing the neurovascular bundles as well as possible, when it’s safe to do so, may be the most important thing a surgeon can do to improve a patient’s quality of life after surgery." These findings have been accepted for publication in the British Journal of Urology International, with a follow-up analysis soon to be published in Urology.

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