A third of men with erectile dysfunction could not perform after taking their first tablet of an impotence drug and gave up sex entirely, according to a study presented at the European Society of Sexual Medicine on 27 November 2007 in Lisbon.

The study looked at 631 men with an average age of 55 who had erectile dysfunction. All had taken medication for their condition and 70 percent were still doing so. 68% of men reported a loss of self-esteem if the pills did not work the first time; 32% felt depressed and 24% said they believed they could never be successfully treated.

One third simply did not go back to their doctor for an alternative treatment after a failed attempt. According to the researchers this highlighted the fact that many men delay treatment, ignore their problem or give up sex completely. 

"These results show the importance of first-time success and many men could potentially see better results by switching tablets or increasing the dose", the researchers noted.

Erectile dysfunction drugs like Viagra, Cialis and Levitra work by increasing blood flow to the genitals.