单项选择题

(A)
When doctors need information about what dose of medicine to prescribe, they usually consult a fat blue book called the Physicians’ Desk Reference, or PDR. But the doses recommended in the PDR may be too high for many people and may cause bad reactions, ranging from dizziness (头晕) and nausea(恶心)all the way to death, according to an article published last month in the journal Postgraduate Medicine.
For many drugs, smaller doses would work just as well, with far less risk of bad reactions, said the author, Jay Cohen, an associate professor at the University of California.
"Side effects drive a lot of people out of treatment that they need," Dr. Cohen said. "People often gave up trying to treat their illnesses when they found that the cure was worse than the disease. But if doctors were to individualize doses for each patient, more people might take their medicine. "
Dr. Cohen said he became aware of the problem because he met many patients who suffered from side effects even though they had taken what were supposedly the correct doses of medicine. When Dr. Cohen consulted medical journals and textbooks, he discovered studies showing that many patients were helped by smaller than usual amounts of medicine. And many of his own patients did better with reduced doses.
Dosing guidelines generally tend to be too high because they are based on studies conducted with limited numbers of patients by drug companies when they are seeking approval for new products, Dr. Cohen said. For those studies to run efficiently, doses need to be high enough to show as quickly as possible that the drug works.
But later, after the drug is approved, far more people take it, sometimes along with other drugs, and individual differences begin to show up. That information does not always make it into the PDR, Dr. Cohen said.
Dr. Cohen cautioned that patients should not try to change doses of prescription on their own. He said they needed to work with doctors to adjust the doses safely. Dr. Cohen pointed out in his article that ______.