Sildenafil - marketed as Viagra -- may not be much help to men who have erectile dysfunction (ED) related to post-traumatic stress disorder, a new study suggests.
Viagra is often effective for ED related to various causes -- including heart disease, high blood pressure and diabetes. But studies indicate that as many of half of men who try the drug do not respond adequately.
In the new study, Iranian researchers looked at whether Viagra was helpful for combat veterans who were suffering from post-traumatic stress disorder (PTSD), as well as ED. It's unclear how many men with PTSD suffer from sexual problems such as ED, although some studies have shown that a majority do so.
The researchers found that the drug appeared no more effective than placebo pills at improving the men's sexual function: 10% of Viagra patients reported normal erectile function by the study's end, compared with 8% of men given a placebo, or dummy pill.
How the study was done
Researchers led by Dr Mohammad Reza Safarinejad, of Shahid Beheshti University Research Centre in Tehran, report the findings in the journal BJU International.
The study included 266 men between the ages of 37 and 59 who had seen combat in the Iran-Iraq war and were later diagnosed with PTSD, and subsequently with "psychogenic" ED -- meaning their erectile problems were believed to have psychological roots.
Half of the men were randomly assigned to take 100 milligrams of Viagra up to two hours before having sex. They were asked to try having sex at least 16 times during the study period. The other half of the study group was given the same instructions but received placebo pills instead of the real drug.
In the end, the researchers found no significant differences between the two groups in terms of erectile function and satisfaction with their sex life.
What the study showed
Safarinejad's team points out that while about half of people with PTSD recover completely in a few months, many others have symptoms that become chronic and debilitating.
The men in this study had long-standing PTSD, suffering from the disorder for an average of about 16 years, and their erectile problems had been present for nearly as long.
It's not clear why Viagra was generally ineffective for them, but it may have to do with how the drug works, according to the researchers. Viagra works by enhancing the effects of nitric oxide, a chemical produced by nerve cells in the penis that relaxes surrounding smooth muscles to allow for improved blood flow and, ultimately, an erection.
But in men with PTSD, the problem may originate farther "upstream" in the central nervous system -- perhaps involving altered activity in stress hormones. – (Reuters Health, August 2009)
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