NEW YORK (Reuters Health) – Sildenafil (Viagra) is associated with a number of side effects, but data on long-term harms are still lacking, a systematic review and meta-analysis has shown.

As reported in the October issue of Urology, Dr. Alexander Tsertsvadze, from Ottawa Health Research Institute, Ontario, Canada, and colleagues analyzed data from 49 randomized placebo-controlled trials of sildenafil identified through a search of MEDLINE, EMBASE, PsycINFO, SCOPUS, and Cochrane CENTRAL.

Men treated with the popular erectile dysfunction drug were 56% more likely than those given placebo to experience any adverse event, the report indicates. Specific side effects linked to the drug were headache (RR = 2.57), flushing (RR = 4.99), dyspepsia (RR = 3.00), and visual disturbances (RR = 3.51).

The results also show that the risk of these adverse events increased as the dose of sildenafil rose.

Rates of serious adverse effects and withdrawals from adverse effects were similar in sildenafil-treated men and those given placebo.

In most of the studies, however, follow-up did not exceed 12 weeks, the authors note.

“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,” the authors conclude. “For example, consideration of flexible dosing regimen of sildenafil to minimize the occurrence of adverse events may be an option.”

Reference:
Urology 2009;74:831-836.