Generics vs. Brand-Name Drugs

As authorized by the 1984 Hatch-Waxman Act, generic drugs must be demonstrated to be “bio-equivalent” to their brand-name counterparts.  There must be an absence of a significant difference in the availability of the active ingredient at the site of drug action.  The authors of this study reviewed thirty-eight randomized clinical trials comparing the clinical differences between generic and brand-name cardiovascular drugs as well as editorial opinions on the same topic.  Data from thirty studies, were used to determine effect size of clinical outcomes.

Clinical equivalence was shown between generics and brand-name drugs for beta-blockers, calcium channel blockers, statins, and warfarin. However, no conclusions could be drawn on diuretics, anti-platelet agents, ACE inhibitors, and alpha-blockers. In fact, only one of the eighteen studies of these drugs enrolled more than 100 patients; only 4 of the studies had thirty or more enrolled patients.
In addition to specific drug classes showing little difference, the aggregate effect size was -0.03 with a 95% confidence interval that crossed zero.  The authors therefore concluded that there was no evidence to deny the clinical equivalence of generic and brand-name versions of several common cardiovascular drugs.  In spite of these data, 53 percent of the editorials on the subject published between 1993 and 2008 express negative opinions on generic substitution.  The discrepancy may be due to anecdotal experience or financial relationships of the editorialists with the brand-name pharmaceutical companies.

Commentary:
Evidence-based medical practice requires that physicians recognize and promote cost-effective, clinically equivalent treatment opportunities.  Though the evidence is limited, physicians should be encouraged to refrain from non-clinically based opinions on pharmaceutical efficacy as it leaves unfettered room for bias.  Additionally, the mere presence of competition within the pharmaceutical industry between brand-name and generic producers provides an opportunity for checks-and-balances that cannot exist within the time frame of brand-name drug patent protection. 

JAMA 2008; 300(21): 2514-2526.
Click here to view an exciting survey of patient’s attitudes about generics in the latest issue of Health Affairs.

by
Kameron Leigh Matthews, MD, Esq.