Are Generic Drugs Truly Bioequivalent to Their Brand Name Counterparts?

Implications: A recent study by ConsumerLab.com suggests that some generic versions of pharmaceutical products may not be bioequivalent to their brand name counterparts. The difference seems to be in the release rates for extended-release (ER) dosage forms as determined by in vitro ("test tube") analysis of dissolution. Patients who report a difference could suffer from the Placebo Effect, or there could be a real and possibly harmful difference.

Analysis:

A recent article by ABC News suggests that generic drugs may not be bioequivalent to their innovator (brand) counterparts. This is a very serious claim - the entire basis for the existence of generics is that they are truly the same as the brand name drug that they replace in every way except price. 

ConsumerLab.com has reported differences in the in vitro ("test tube") dissolution values for some extended release (ER) generic drugs, and the ABC News article implies that this difference could lead to patient harm. The FDA's primary focus in approving ANDAs is that bioequivalence has been demonstrated. This is almost always done via an in vitro dissolution test. Even across batches of a branded drug, there often will be small differences in release of the active in the first hour, but these are deemed insignificant. For a particular drug such as Wellbutrin, once steady-state blood levels are achieved, small differences in dissolution shouldn't have much, if any, impact on the drug's efficacy. One wonders how much the placebo effect comes into play in cases like this.

As a long-time member of the branded pharmaceutical industry, I'm confident that generic drugs are equivalent to their brand name counterparts. The system that has been established to assure generic drug quality is the same system that is in place for branded drugs, and I have no reason to think that the folks who manage or work in the generic industry have any less concern for the quality of their product than those in the innovator companies.