Afraid the generic isn't as good as the original brand name drug? You needn't be, according to a review of randomized clinical trials that appears in today's Journal of the American Medical Association.

Aaron Kesselheim and colleagues at Brigham and Women's Hospital in Boston reviewed the limited number of studies that compare generic cardiovascular drugs to their original patented versions. Most of these trials were small because they only sought to show bioequivalence. The Food and Drug Administration allows a generic on the market once its manufacturer shows that the drug has the same physical properties of the original drug. The generic manufacturer need not replicate the original efficacy trials.

Still, in 47 studies involving eight different classes of heart drugs (including beta-blockers, calcium channel blockers, diuretics and ACE inhibitors), the authors found essentially no clinical difference in the variables measured by the bioequivalence studies.

For example, they found seven articles comparing generic and brand-name calcium channel blockers. The largest involved just 189 high blood pressure patients who were given either amlodipine (Norvasc by Pfizer) or its generic equivalent. Results? The study "found improvements in blood pressure and no significant differences between brand-name and generic versions."

However, when the reviewers turned to evaluating medical journal editorials on the wisdom of generic substitution, they found a very different story. Most of the editorials appeared in peer-reviewed journals that cater to narrow segments of the cardiology community.

Kesselheim and colleagues discovered that more than half (53 percent) of the 43 editorials viewed generic substitution in a negative light. Only 28 percent thought it was okay (eight editorials had no opinion, a curious outcome for an editorial).

What might account for the disconnect between the facts about bioequivalence and the stance of the editorials? The reviewers speculated it might have been personal anecdotal experience, or:

Another possible explanation is that the conclusions may be skewed by financial relationships of editorialists with brand-name pharmaceutical companies, which are not always disclosed. Approximately half of the trials in our sample (23/47, 49 percent), and nearly all of the editorials and commentaries, did not identify sources of funding.

For instance, Columbia University's James A. Reiffel wrote in 2000 in the American Journal of Cardiology that "despite their reported bioequivalence, the generic agents involved were clearly not therapeutically equivalent." I checked the journal's guidelines for authors. It still does not require conflict of interest disclosure.

I can't figure out if Reiffel was taking money from industry in 2000, but in a Medscape continuing medical education disclosure form filed in 2007, he revealed that he has received grants and served as a consultant for numerous drug and medical device companies.

So, if you're still wondering whether that generic you're taking to save yourself or your insurance company some money is as good as the brand name drug, do yourself a favor and read the studies. But pay no attention to that man in the corner writing the editorials.