March 6 (CBSHealthWatch)--Critical information about Viagra may not have been readily available to those who need it, according to a review of literature on the subject.
Jay S. Cohen, MD, associate professor of family and preventive medicine at the University of California at San Diego, reviewed product package inserts (the information provided with the drug that lists its side effects and other clinical data) that were issued between March 1998 and January 2000, the 2000 Physician's Desk Reference (PDR), and unpublished data from drug's maker, Pfizer.
"The information that is given in the package inserts and the PDR sometimes is very good, but sometimes is quite lacking," says Cohen. "Coincidentally, the FDA is now in the process of reorganizing package inserts so the information will be better presented. That's good, and I support that. But at the same time, the quality and depth of the information also needs to be improved. "
Cohen says doctors and patients need to know more about Viagra's effects on blood pressure, expected patient responses to different dosages of the drug, the known consequences or safety of the drug for some high-risk patients (such as older patients and those with heart disease), and important drug interactions.
Such information has reportedly been limited or was not included in the first package insert issued for Viagra, but Cohen says the data could have helped doctors make more informed prescribing decisions. As an example, he cites how important it is for physicians to know more about Viagra's tendency to lower blood pressure.
"One of the biggest questions about Viagra is 'Does it affect blood pressure? How does it affect blood pressure? And does its effects on blood pressure have anything to do with the number of deaths and heart attacks and strokes and people passing out?'" he asks. "For me and for, I think, so many other doctors there's been a question, 'In a rare individual, can Viagra really drop blood pressure in a significant and perhaps a dangerous way?'"
As with every new drug, Cohen acknowledges that it is difficult for studies to cover every single outcome. He says, however, that it is unrealistic to expect doctors to re-read package inserts every time new information comes out about the drug, given their busy schedules. It's best that package inserts be as comprehensive as possible the first time around, he says.
It is a challenge for doctors to keep up with the constant flow of new information about drugs and illnesses, but at least one expert says both physicians and patients need to know as much as possible before a drug is prescribed or taken. "If you're prescribing a drug, you'd better know what the dangers of using that drug are," says Melvin Cheitlin, MD, former chief of cardiology at San Francisco General Hospital. "And the patient should always ask, 'What are the problems with this drug?'"
Another expert, Howard Herrmann, MD, director of interventional cardiology and professor of medicine at the University of Pennsylvania Medical Center, agrees. In addition, he recommends that physicians and patients discuss the following before using Viagra:
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