New medications
from the same drug family as Viagra are on the horizon and researchers
say they work faster and last longer than the widely popular treatment
for male erectile dysfunction.
"Vardenafil
and Cialis are better drugs than Viagra," Dr. Irwin Goldstein, professor
of surgery at Boston University, said at the American Urological Association
annual meeting.
"We expect we
will have these drugs on the market in 10 to 12 months."
Vardenafil,
manufactured by Bayer Corp., appears to be faster acting than Viagra, works
longer and allows up to 80 percent of men taking it to overcome erectile
dysfunction sufficiently to engage in successful intercourse, Goldstein
said.
Cialis, a drug
manufactured by Eli Lilly & Co., also appears to act more quickly than
Viagra. Research also shows it continues to work for 24 hours or longer,
meaning patients could take one dose in the evening, engage in intercourse
at that time, and respond again in the morning or later the next day without
requiring another pill, said Dr. Harin Padma-Nathan, clinical professor
of urology at the University of Southern California in Beverly Hills.
The manufacturers
of both drugs plan to file for Food and Drug Administration approval before
the end of this year.
In a presentation
at the AUA meeting, Padma-Nathan said 74 percent of men responded to high
doses of Cialis within 30 minutes and about 76 percent were still able
to respond to the drug 12 to 24 hours later.
"The 20-milligram
dose of Cialis enabled the onset of erection sufficient for completion
of intercourse as early as 16 minutes," Padma-Nathan said. "The period
of responsiveness lasts to at least 24 hours, enabling multiple successful
intercourse attempts."
Goldstein said
Vardenafil was more potent than Viagra, requiring smaller doses of the
drug, which reduces the chance of side effects. He said while the long-term
of action for Cialis might be considered a positive, he was concerned there
was not enough clinical data available to determine if long-term suppression
of key molecular activities involved with use of the drug is harmful.
In the Vardenafil
data presented by Dr. Jay Young of the South Orange County Medical Research
Center in Laguna Woods, Calif., researchers showed that at all doses Vardenafil
significantly improved erectile function, orgasmic function, intercourse
satisfaction and overall satisfaction when compared with placebo.
"Vardenafil
showed an improvement in the proportion of successful attempts at intercourse
during the first four weeks of the study and that improvement was maintained
over the 12-week study period," Young said.
Neither Vardenafil
nor Cialis have been tested in patients in head-to-head comparisons with
Viagra or with each other. Goldstein suggested if the manufacturers are
reluctant to do such testing then individual clinicians who specialize
in sexual medicine would conduct some tests on their own.
Aside from drugs
that impact the phosphodiesterase type 5 system -- Vardenafil, Cialis and
Viagra -- numerous other drugs are being developed to treat erectile dysfunction,
said Dr. Ridwan Shabsigh, associate professor of urology, Columbia University,
New York.
Among those
closest to the marketplace is Uprima or apomorphine, a drug absorbed under
the tongue. While the other drugs operate on functions in the penis, Shabsigh
said, apomorphine works in the brain to activate receptors essential in
erectile function. The drug is approved in Europe but its approval in the
United States has stalled.
Topiglan, a
topical gel rubbed on the head of the penis, is in clinical testing, Shabsigh
said, and added it is one of several topical medications being developed.
--
Copyright 2001 by United
Press International.
All rights reserved.
--
|
