WebMD Medical News
Louise Chang, MD
May 29, 2008 -- The erectile dysfunction drug Levitra is getting a label
change noting rare reports of transient global amnesia in men taking the
Transient global amnesia, or TGA, is a brief bout of amnesia, not lasting
longer than a day, without causing other problems.
Levitra's label change isn't a warning or a precaution, and it doesn't mean
that the drug causes memory problems. The reported cases of transient global
amnesia in men taking Levitra may have been spurred by something else, even by
"Sex can trigger TGA," says Harvard neurology professor Louis R.
Caplan, MD. He likens TGA to a tape recorder that's not working.
"People otherwise can walk and talk and read and do high-level things,
but they're not recording the information, as if their tape recorder is
off," Caplan explains.
Transient global amnesia "scares people" but it doesn't affect
function, long-term memory, or other aspects of health, Caplan says. "It
isn't a reason not to take the drug."
Still, men who experience transient global amnesia should see a doctor to
rule out illness or injury, says Caplan, who is also an attending physician in
the Comprehensive Center for Stroke and Cerebrovascular Diseases at Beth Israel
Deaconess Medical Center in Boston.
Transient global amnesia will join a list of other rare, reported adverse
events -- including vision problems and sudden hearing loss, which are noted
for all ED drugs -- in the "Post-Marketing" section of Levitra's
Levitra's label got the transient global amnesia note "because of a
limited number of post-marketing reports of men who experienced TGA" around
the time they took Levitra, the FDA tells WebMD in an email.
But those reports don't prove that Levitra was to blame.
Bayer Pharmaceuticals and the FDA have agreed on the wording of Levitra's
label change, Bayer Pharmaceuticals spokesman Mark C. Burnett tells WebMD by
email. Bayer "constantly monitors product safety reports and works closely
together with worldwide regulatory authorities, including the FDA, to ensure
that appropriate product information is shared with physicians and with their
patients," Burnett says.
Caplan, a transient global amnesia expert, has seen many TGA patients, but
only one man who had TGA after taking an ED drug.
The patient, a 51-year-old man with a history of hypertension and migraines, had played
golf in the morning. After returning home with his girlfriend, he took
"After 30 minutes, as he was about to engage in sexual intercourse, the
patient reported that he 'felt weird'... [and] could not remember that he had
played golf that morning," Caplan and colleagues wrote in
Neurology's Sept. 10, 2002, issue.
The man was hospitalized for a day. His memory gradually improved during
that time, though he hadn't regained his lost memories when he was discharged
from the hospital.
Few other cases of transient global amnesia in men taking ED drugs have been
published in medical journals. Those cases include a German man who experienced
TGA after he apparently took Cialis, his doctors wrote in the International
Journal of Impotence Research's July/August 2005 issue.
None of the case reports confirm that ED drugs prompted transient global
The three erectile dysfunction drugs -- Cialis, Levitra, and Viagra --
belong to a class of drugs called phosphodiesterase type 5 (PDE-5) inhibitors.
None has been shown to cause transient global amnesia.
Only Levitra is changing its label to note reports of transient global
amnesia. The FDA tells WebMD it can't comment on whether the makers of Cialis
and Viagra have been asked to make similar label changes.
Pfizer makes Viagra. "We can't really speculate whether the Viagra label will be
updated, but we certainly do believe that the current label accurately reflects
the safety and efficacy of Viagra," Pfizer spokeswoman Jennifer Jacob tells
WebMD in an email.
Eli Lilly & Co. makes
Cialis. "Lilly typically doesn't discuss potential label changes or
regulatory action," Stephanie Kenney-Andrzejewski, senior vice
president for communications firm MS&L Global Health, tells
WebMD on behalf of Lilly in an email. Kenney adds that "Cialis
continues to be a generally well-tolerated and effective treatment for
ED," with a safety profile backed by clinical research in more than
16,000 patients and more than 11.5 million men worldwide who have been
SOURCES:FDA, letter to Bayer Pharmaceuticals.Louis R. Caplan, MD, professor of neurology, Harvard Medical School; chief,
cerebrovascular/stroke division, Beth Israel Deaconess Medical Center,
Boston.Mark C. Bennett, spokesman, Bayer Pharmaceuticals.Savitz, A. Neurology, Sept. 10, 2002; vol 59: p 778.Schiefer, J. International Journal of Impotence Research, July/August
2005; vol 17: pp 383-384.FDA, statement emailed to WebMD.Jennifer Jacob, Pfizer.Stephanie Kenney-Andrzejewski, senior vice president, MS&L Global
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