Cincinnatti—Patients frequently complain that, despite a requirement that approved generics be equivalent to their brand-named counterparts, switching from one generic to another makes a difference in their therapy response—an especially significant problem when drugs are prescribed to control severe, chronic conditions such as seizures.

That’s why a study published online recently by The Lancet Neurology evaluated clinical effects in two generic lamotrigine products to control epilepsy. No detectable differences were found.

“Study results show that as long as patients adhere to their treatments, the two generics did not show any difference in their bioequivalence,” said lead author Michael Privitera, MD, of the Epilepsy Center at the University of Cincinnati Neuroscience Institute.

“Consequently, it should give increased confidence to both clinicians and patients that existing regulations are providing generic drugs that can be safely substituted, even in cases where medicine is life-saving. Patients can now feel safe about substituting generics (of their antiepileptic drug) without concerns of interactions or undesired effects.”

Background information in the report notes that several previous uncontrolled studies suggested risks with generic switching, while other studies found no such risk. Concern that the FDA was allowing too much variability across formulations, the American Epilepsy Society (AES), the American Academy of Neurology, and other professional societies had opposed patients substituting antiepileptic generics without consent of the physician or patient.

Yet, study authors point out, the need for effective generics is essential to patients, with the FDA estimating $230 billion per year is saved by generic substitutions.

The FDA joined with AES and the Epilepsy Foundation (EF) to fund the EQUIGEN trial, which used two generics considered to be the most disparate products on the market, and in a double-blind study, switched patients from one generic to the others throughout the course of the trial.

For the study, researchers focused on 35 adults with epilepsy who currently use lamotrigine, comparing long-term dosing using the two currently on-market antiepileptic generic drugs. Patient diaries, electronic medication monitoring and tablet counts were employed to keep adherence to nearly 100%.

Lamotrigine was considered the ideal drug for the assessment, because of its sensitivity and because of complaints to the FDA about problems with generic switches, Privitera said. Even though no differences were found, he suggested explanations for the previously reported inconsistencies.

“One is the ‘nocebo’ effect, where patients and clinicians expect the generic products to be inferior, so the therapeutic effect is assumed to be reduced,” Privitera said in a University of Cincinnati Academic Health Center press release. He also said pill confusion with changing color or shape among generics could have an influence or that the quality of generics could have improved over time.

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