Are generic drugs as good as their brand name counterparts?

DEAR DOCTOR K:

My doctor switched me from several brand-name drugs to generic versions of those drugs. It has saved me a lot of money — but are they really as good for me?

DEAR READER:

The vast majority of generic drugs have been shown to be equally effective as brand-name drugs, and no more likely to cause side effects. There have been a few exceptions, which I’ll mention. But that is my bottom line — and I vote with my feet: I take generic drugs. They work as well as the brand-name drugs they replaced, they haven’t caused side effects and they save me money. What’s not to like?

Drugs available in the United States are carefully examined by the U.S. Food and Drug Administration (FDA). The FDA makes sure that a generic drug has the same chemical structure as a brand-name drug, and that the generic drug behaves the same way in the body.

Still, once the FDA has released a generic drug for widespread use, a much larger number of people take it than was true when it was being tested in the pre-approval period. That means that rare problems may emerge in the post-approval period.

There have been many careful studies comparing generic drugs to their brand-name equivalents in the post-approval period. Almost always, the generics prove identical. However, there have been a few instances where the generic drug was not equivalent — at least until a problem in the manufacturing process was corrected. Examples include some generic drugs to treat underactive thyroid (hypothyroidism).

In late 2015, an expert committee of the American College of Physicians summarized what is known scientifically about generic drugs. The committee’s report agrees with what I have said. The report also summarizes evidence that generic drugs often are not used when they could be. One study published in 2013 found that the brand-name versions of several popular drugs were used 23 percent to 45 percent of the time when generic versions were available.

The report also pointed out a problem with taking brand-name drugs instead of generic versions: a person might get fewer health benefits. Why is that? Any medicine will work only if it is taken. And many studies have found that people are less likely to take brand-name drugs when they are prescribed than they are to take generic drugs when they are prescribed. That’s probably because the brand-name drugs cost more.

While I believe the evidence shows that almost all generic drugs perform as well as brand-name drugs, that evidence is based on the “average” person in studies typically involving hundreds or thousands of people. Now and then I have a patient who swears that a generic drug is not as effective as the brand-name drug. It is possible that the patient’s body chemistry is different in some way from that of the average person. So I prescribe the brand-name drug — but the insurance company determines how much more the patient will have to pay.