FDA: Viagra Safe Despite 101 Reports of Adverse Events
June 26, 1998 5:21 PM
By Otesa Middleton
WASHINGTON (Dow Jones)--The U.S. Food and
Drug Administration continues to receive reports of
serious health problems among a handful of men taking
Pfizer's Viagra, but the agency still considers the drug
safe and effective.
According to the FDA's most recent adverse-event data
for Viagra, there were 101 such reports, some of them
duplicates.
The FDA isn't alarmed by the reports because a direct
link to Viagra, the blockbuster male impotence drug,
hasn't been established, and Pfizer says the number is
small considering the 2.5 million prescriptions written for
the pill.
"We continue to believe the drug is safe and effective for
the intended patient population," said Susan Cruzan, an
FDA spokeswoman. "We will continue to monitor the
reports for any kind of trend."
The report lists 29 deaths, 15 vision-related problems
and several heart attacks and increased heart rates.
Pfizer (PFE) said it is required to report every possible
case of an adverse event, and some instances are listed
in the FDA's database more than once because the
same incident may have been reported by different
people.
"We get our reports from our sales reps, individual
physicians and hospitals and we also process news
reports," said Andy McCormick, a Pfizer spokesman.
For example, the database lists four cases of blindness in
West Virginia. McCormick said the reports came from a
salesperson who heard it from an osteopath, who heard
that four men went blind while taking the drug. The
company had to file the report within 15 days, according
to FDA guidelines and couldn't find any additional
information about the situation.
"Everything we have seen in terms of side effects is well
within what we expected in the patient population,"
McCormick said.
Since Viagra hit the market in April, Pfizer said two
million men have tried the drug. Scott-Levin, a
health-care market research company, said $135.5
million of Viagra was sold by the end of May.
McCormick called the FDA's adverse-event report
"reassuring" since 85% of prescriptions are written for
men over age 50.
Dianne L. Kennedy, a pharmacist and epidemiologist at
the FDA, said when any drug first hits the market the
agency watches it closely.
"It is impossible to pick up all of the safety problems in
clinical trials because of limitations," Kennedy said. "A
clinical trial is very controlled, but when it gets to the
general population a drug is used in people with other
diseases and who are taking other medications."
Those other medications concern Dr. Charles L. Curry,
chief of cardiology at Howard University's College of
Medicine in Washington. He agrees that the reports
aren't cause for alarm, but he wants to know more.
"We need more information on how Viagra works with
other drugs," Curry said.
"It may be beneficial to study possible adverse drug
interactions in a scientific way," Curry said.
Doctors Seek More Screening Guidance
Before Viagra's approval, Pfizer tested it for interactions
with alcohol, common antacids, aspirin and
blood-pressure medicines.
Curry, the Howard University College of Medicine chief
cardiologist, said he wants to see a study of Viagra's use
with a short-acting hypertension drug. Pfizer tested the
drug's use with Norvasc, which Curry said takes longer
to lower the blood pressure. Since Viagra acts quickly,
it may have different interactions with a drug like
Cardura, which sometimes causes a sudden drop in
blood pressure.
"Some patients faint after the first dose of Cardura,"
Curry said. "That is the most worrisome combination I
imagined."
The FDA report lists three cases of men also taking
Cardura.
Pfizer's McCormick said the company chose to test
Norvasc in clinical trials because it is so widely
prescribed.
According to Scott-Levin, the health-care market
research company, 17.8 million prescriptions were
written for Norvasc last year compared to 6.9 million for
Cardura.
Dr. Kevin T. McVary, impotency expert and associate
professor of urology at Northwestern University
Medical School in Chicago, said the reports of adverse
events doesn't concern him.
"My suspicion is that Viagra isn't increasing the number
of guys having heart attacks," said McVary, who has
written several hundred Viagra prescriptions.
Dr. Lloyd W. Klein, professor of medicine and director
of interventional cardiology at Rush-Presbyterian-St.
Luke's Medical Center in Chicago, said he would like to
see more guidance from Pfizer about how to screen
patients before prescribing them Viagra.
"The company needs to come out with a set of
guidelines or rules," Klein said.
The Viagra labeling says: "A thorough medical history
and physical examination should be undertaken to
diagnose erectile dysfunction, determine potential
underlying causes and identify appropriate treatment.
"There is a degree of cardiac risk associated with sexual
activity: therefore, physicians may wish to consider the
cardiovascular status of their patients prior to initiating
any treatment for erectile dysfunction."
Klein said he wants Pfizer to tell him exactly what type
of tests should be performed before he gives his patients
Viagra.
"If someone has chest pain when they climb two flights
of stairs, it's common sense you wouldn't prescribe
Viagra until there is further testing," Klein said. "But what
about males over 50 who have heart disease that hasn't
declared itself?"
Klein said before he writes a Viagra prescription he has
his patients undergo a stress test and makes sure they
aren't taken nitrates, the only drug for which Viagra is
contraindicated.
It is difficult to determine if a drug interaction has caused
some of the adverse events or if underlying illness is to
blame, Klein said.
"That is the $64,000 question," Klein said. "Nobody
knows."
-Otesa Middleton 202-862-6654 |
