New Impotence Drugs Nearing Approval
Promise to Deliver Faster Erections for Longer
May 28, 2002 -- Two new contenders have emerged to challenge Viagra, which has dominated the erectile-dysfunction drug market since its introduction in 1998. The new drugs promise to deliver faster erections for a longer time.
Both Cialis and vardenafil are in the last phase of research before FDA approval. Lilly, one of the developers of Cialis, is a WebMD sponsor. Erectile dysfunction specialists presented the most recent findings on these upstart drugs at a recent meeting.
One group reported that men can get an erection up to 36 hours after a single dose of Cialis. In the study, 348 men took either Cialis or a placebo. They were asked to try to have sex 24 hours after taking the pill on two separate occasions, and then try two more times 36 hours after the dose.
Of the men who took Cialis, 57% were able to have sex 24 hours later, and 60% were able to do so 36 hours after taking the drug. In comparison, Viagra's effect lasts about four hours. Plus, Cialis starts working about 15 minutes after taking it -- compared with 30-60 minutes for Viagra.
"Cialis is a very interesting drug," says Myron Murdock, MD, who is on the medical advisory boards for Cialis and vardenafil. Although these results show that Cialis works for up to 36 hours, "in reality, it's probably up to 72 hours," Murdock says. "Somebody who is going to have a significant amount of sexual activity can take two pills a week, and be prepared for the week."
The drug might not last so long in all men, according to Cialis researcher Hartmut Porst, MD, of Hamburg, Germany. "It depends on individual circumstances," he says.
Some fears about such a long-lasting drug have been raised, but dismissed. Do men who take it stay erect for days? No, the researchers say. That does not happen, nor do the drug's potential side effects -- headache, backache, facial flushing -- last as long as the erection-enabling effect does. "That was surprising to all of us," Porst says.
The researchers studying vardenafil emphasized a different angle: It works for men with severe erectile dysfunction.
They presented the results of two studies in which more than 1,300 men took vardenafil or a placebo.
Thirty-nine percent of the men with severe erectile dysfunction were able to have sex after taking vardenafil. That's compared with only 2.5% of the men who took the placebo. Vardenafil worked for men with less severe erectile dysfunction, too. More than 70% of those with mild problems and about half of those with moderate problems had normal erections after taking it.
Vardenafil is more like Viagra than Cialis is. "I think the major advantages of vardenafil over [Viagra] are really not great," Murdock says. "They both appear to work about the same."