term harms are still lacking, according to a review of 49 published studies.
In the
medical journal Urology, Dr. Alexander Tsertsvadze, from
Ottawa Health Research Institute,
Ontario, Canada,
and colleagues report
that men who took Viagra, also known as sildenafil, were
56 percent more likely than those given a placebo to experience any side effect.
Specific side effects commonly reported by men using Viagra were headache, flushing difficulty breathing, and vision problems.
The results also show that the risk of these side effects increased as the dose of Viagra rose.
The researchers say more studies are needed with longer follow up, which did not exceed 12 weeks in the studies reviewed.
"More efforts should be directed toward achieving an optimal
balance between the degree of effectiveness and safety of sildenafil use in men
with erectile dysfunction," they conclude.
"For example, consideration of flexible dosing regimen of
sildenafil to minimize the occurrence of
adverse events may be an option," they
wrote.
SOURCE: Urology, October 2009.
