Up to one fifth of all new prescription drugs may ultimately be
recalled or produce potentially harmful side effects, a recent
“The safety of new agents cannot be known with certainty until a
drug has been on the market for many years,” according to the
The study results are based on an evaluation of the 548 drugs
that were first marketed between 1975 and 1999. The researchers
looked up all drug recalls and scanned the Physician’s Desk
Reference, a commonly used source of drug information, for new
warnings on side effects. During the study period, 10% of new
drugs either received new warnings or were withdrawn, with half
of those developments occurring within 7 years after the drug
first appeared on the market. Based on these results, it was
calculated that a new drug has a 20% chance of being withdrawn or
producing previously unknown side effects over a 25-year period.
Side effects from new drugs can have a widespread impact. Almost
20 million Americans took one or more of the five drugs that were
withdrawn between September 1997 and September 1998.
They found that 56 of 548 new drugs approved by the agency during
the 25-year period were later subjected to so-called “black box”
safety warnings or banned from the market altogether. FDA uses
“black box” warnings on drug labels to warn physicians of
potentially dangerous side effects or drug interactions.
In some cases, those side effects can be deadly: Since 1993,
seven drugs that were approved (then later withdrawn) may have
contributed to over 1,000 deaths.
A total of 81 major label changes or drug withdrawals occurred
during the study period.
Several high-profile drugs have been pulled from the market by
regulators over the last few years. One drug, the antihistamine
terfenadine (Seldane), spent nearly 13 years on the market before
being banned in 1998. Another, the gastrointestinal drug
cisapride, was available for over 6 years. Both drugs were pulled
because researchers discovered high rates of heart toxicity
associated with their use.
The researchers believe that fewer than 1 in 10 adverse drug
reactions are reported to the FDA. New drugs may be causing more
harm than this study illustrates. “Our study is definitely an
underestimate of what is going on,” Dr. Karen E. Lasser said.
Drugs that are withdrawn or cause previously unknown side effects
after being approved were clearly not properly evaluated, she
If you are on medications, or plan to take a new one, we advise
you to consult
with one of our physicians. We have an array of alternative
therapies that you may be able to utilize to achieve the same
result as a drug, but without the side effects.
Source: Journal of the American Medical Association