What You Need to Know About Generic Drugs

By Tod Cooperman, MD, President, ConsumerLab.com

Posted on | By Tod Cooperman, MD | Comments ()

More than 80% of the drugs we take in the US are now generic versions of brand name medications. You may think that these drugs are equivalent to their branded counterparts, but that’s not always the case. Here are some important facts and tips to stay safe with generic drugs.

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Fact: You may get more or less active drug from a generic.

The FDA only requires that you get 80% to 125% of the drug into your bloodstream from a generic medication compared to the original drug. What’s even more concerning is that there are often many different generic versions of the same drug, and each of these may be different as well. Consider this: If you take a generic which only meets the minimum requirement and refill that prescription with one that’s at the maximum limit, you’ve potentially increased the amount you get into your body by as much as 45% percentage points – and you would have no way of knowing this from the labels, but it could certainly affect you. The opposite could also happen, and you would be getting a lot less drug than you were previously – which could also affect you.

This is particularly troubling for medications for which blood levels must be kept in a narrow range in order to be effective and/or to avoid toxicity. These can include:

  • Thyroid medication
  • Anti-seizure medication
  • Blood thinners
  • Antidepressants
  • Antipsychotics
  • Asthma medications
  • Immunosuppressants 

Fact: Other than the active ingredient, a generic may contain very different other binders and fillers.

Most of the ingredients in a pill are not the active ingredient but other ingredients needed to hold the pill together, coat it, and control the way the pill delivers its drug in your body. These other ingredients can be different in a generic version of a drug. It is possible to have an allergic reaction or sensitivity to one of these ingredients. With some extended-release products, the brand name formula is still patented, so the generics may be completely different in their formulation. This can affect how fast or slow they release their drug and how this is affected by things like whether you take the pills with food or not.

Fact: Generics are not tested like brand name medication.

While brand name medication is tested for safety and efficacy before being approved, generics are not. The only human test in people that is required is a bioequivalence test, conducted by the manufacturer in a small number of healthy individuals. This test must show that the product delivers approximately the same amount of drug into your blood stream and approximately the same rate.

Fact: Labels on most generic drugs are incorrect.

The FDA requires that the package inserts for generic drugs show the data (the “pharmacokinetic” data) from the brand name medication as if it is were based on the performance of the generic drug. In actuality, the data for the generic is typically different, but the FDA does not release this information.

Article written by Tod Cooperman, MD
President, ConsumerLab.com