Are Generic Medications the Same as Branded Counterparts?

What is a Generic Drug?

The active ingredient of a 'generic' medication (for example, of 'generic Paxil', which is Paroxetine) is chemically identical to the active ingredient of the corresponding branded medication. Because generic medications are often much cheaper than their branded counterparts, very many people choose generics (whether buying discount medications online or in traditional retail outlets), and many insurance companies actually require that they be used.

According to the FDA's Office of Generic Drugs:

A generic drug is identical, or bioequivalent to a brand name drug in dosage form, safety, strength, route of administration, quality, performance characteristics and intended use. Although generic drugs are chemically identical to their branded counterparts, they are typically sold at substantial discounts from the branded price.According to the Congressional Budget Office, generic drugs save consumers an estimated $8 to $10 billion a year at retail pharmacies. Even more billions are saved when hospitals use generics.

Are There Any Differences Between Generics and Brand-Name Drugs?

However, it should be noted that current regulations permit a variation of approximately 20% either way in the bioavailability of the active ingredient. (The specifics of the permitted variation in bioavailability hinge on the FDA's technical definition of bioequivalence, which requires that there be no statistically significant difference in bioavailability. For the FDA's definition, see the agency's Guidance for Industry document, which sets out guidance on confidence intervals for test to reference comparisons across different types of medications, as well as the FDA's Code of Federal Regulations 320 document on bioavailability and bioequivalence requirements. Also see this 1999 Food and Drug Law Institute overview of the Hatch-Waxman Act of 1984.) In one study (Borgheini 2003), a full 31% variation was found in the blood plasma levels of a particular medication after a patient switched from a branded to a generic product. (Why does this happen? It may be accounted for by differences in the manufacturing process yielding different particle sizes that are absorbed at different rates, as well as other factors.)

The Bottom Line on Generic vs. Brand-Name Drugs

This does NOT necessarily mean that purchasing generic medications in preference to branded counterparts is a bad idea -- in fact, in most cases it is probably still a very good idea! -- but this does mean that the issue is not quite as clear cut as it might otherwise seem.

In my view, provided medications are taken under the supervision of a qualified medical professional, there is very little advantage to buying branded medications if cheap generic drugs are available. The only difficulty, of course, is that it sometimes takes many decades before generics actually do become available. (See the separate page of background to the controversy about discount drugs.)