Dr.Joe's Data Base

Wednesday May 13 6:03 PM EDT
Viagra effective and well tolerated: study
NEW YORK (Reuters) -- Reports in the news media about use of oral
sildenafil (Viagra) to treat erectile dysfunction have been
circulating since late March, when the US Food and Drug
Administration approved the drug. A study published this week in The
New England Journal of Medicine confirms that the drug is "an
effective, well-tolerated treatment for men with erectile
dysfunction."

In the article, a multicenter team led by Dr. Irwin Goldstein of
Boston University Medical Center in Massachusetts, describes a series
of trials with the drug. In the first phase, which lasted 24 weeks,
532 men were treated with either 25, 50, or 100 milligrams of
sildenafil, or placebo. In another phase, 329 men were treated
initially with 50 mg of sildenafil or placebo, with the dose
increased up to 100 mg. Finally, for the last phase of the study, 225
of the these 329 took sildenafil for another 32 weeks. In all cases,
the drug was taken approximately 1 hour before planned sexual
activity, but not more than once daily.

The effectiveness of the treatment was determined on the basis of a
questionnaire, a log that patients kept at home, and a global
efficacy question. Goldstein and his colleagues comment, "In keeping
with sildenafil's mode of action (i.e., the drug causes erection only
in response to sexual stimulation), the studies were performed
entirely in a natural environment, which meant that we had to rely on
the men's own reports of efficacy."

According to the article, increasing doses of the drug were
associated with highly significant improvements in erectile function.
Men treated with 100 mg of sildenafil scored 100% higher on the
question about achieving erections, the investigators said.

"In the last four weeks of treatment in the dose-escalation study,
69% of all attempts at sexual intercourse were successful for the men
receiving sildenafil, as compared with 22% for those receiving
placebo," the researchers report. Men treated with sildenafil
reported an average of 5.9 successful attempts at intercourse per
month, versus only 1.5 successful attempts per month among men in the
placebo group.

The most common side effects of the drug were headache, flushing, and
dyspepsia.

"Oral sildenafil is an effective, well-tolerated treatment for men
with erectile dysfunction," Goldstein and his colleagues conclude.

Inn accompanying editorial, Dr. Robert D. Utiger explains that
sildenafil is only effective when production of cyclic guanosine
monophosphate, which stimulates relaxation of smooth muscles, is
increased in penile tissue by sexual arousal. "Thus," he writes,
"sildenafil will be ineffective if there is no arousal, enhancing the
role of the man's partner." He adds that "....treatment would
probably (not) be effective in men with erectile dysfunction caused
by severe arterial insufficiency, loss of trabecular smooth muscle,
or incompressible cavernosal veins."

Utiger continues, "The availability of sildenafil... means that many
more men will seek help for (erectile dysfunction) and that primary
care physicians will be increasingly involved in making decisions
about the evaluation and treatment of these men.... Whether the
promise of sildenafil will be realized after many more men have been
treated and the drug has been taken repeatedly for prolonged periods
remains to be seen." SOURCE: The New England Journal of Medicine
(1998;338:1397-1404, 1458-1459)

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