Generic Versus Branded Drugs: Concerns Amidst Limited Evidence
Posted by medliorator on September 18, 2009
Many physicians have found [the switch to generic drugs] particularly problematic in classes of drugs with a narrow therapeutic range, including antiepileptics, psychotropics, antiarrhythmics, and anticoagulants.
although the generic’s mean maximal concentration and area under the concentration-time curve are typically within a few percentage points of the original’s — typically about 4% — the 90% confidence interval for those means can be 20% below or 25% above the branded drug’s mean.
much of the current evidence of problems with generic antiepileptics is anecdotal, or comes from retrospective or case-control studies — not randomized controlled trials. But all of those studies have come to similar conclusions.
Two retrospective studies published last year in Neurology found that patients who had events like break-through seizures were much more likely to have been switched from a branded product to a generic… “Brand-to-generic seems to be the biggest issue,” Meador said. “But generic-to-generic seems to confer some risk as well.”
some non-SSRI antidepressants aren’t so forgiving, said Jeffrey Lieberman, MD, a psychiatrist at Columbia University in New York City. He mentioned the tricyclic drug nortriptyline and bupropion (Wellbutrin) as more susceptible than most antidepressants to dosage variations.
Generics versus Brands: How It Plays Out in Practice [Medpage Today]
