Are generic drugs truly equivalent to brand name medications?

In an effort to cut prescription drug costs, there is constant pressure to switch from brand name medications to their generic equivalents.

But in this special report from MedPage Today, there may be some variability between generic medications that can lead to clinical symptoms. However, most of the data is anecdotal, and at best, based on retrospective data.

For instance, when it comes to anti-seizure medications, some neurologists are cautioning about switching to generic drugs, as “for antiepileptic drugs, the window is narrower and the short-term consequences of changes in drug blood levels are greater.”

Generic drugs gain FDA approval by showing they are bioequivalent to the branded original. But, “although the generic’s mean maximal concentration and area under the concentration-time curve are typically within a few percentage points of the original’s — typically about 4% — the 90% confidence interval for those means can be 20% below or 25% above the branded drug’s mean.”

Although that may be acceptable for some classes of drugs, like antibiotics, for instance, some are arguing that this may be too loose a definition for drugs that require a specific blood level, like blood thinners or anti-seizure drugs.

Generic medications are a clear source of cost savings, which is why both the government and private insurers are making a hard push to convince both doctors and patients to switch. I continue to support the use of generic drugs, but there is growing sentiment that more rigorous study is needed to ensure that there will be minimal adverse effects when switching.