No Difference in Efficacy Between Generic Seizure Drugs, Study Show

Earlier studies suggested risks could exist when switching between generics.
Earlier studies suggested risks could exist when switching between generics.

No detectable difference was measured in clinical effects when two generic antiepileptic drugs were tested among patients, results from a study has shown. The findings are published in The Lancet Neurology

Approved generic products are required to have the same active ingredient as the brand name product but many wonder if switching between generic products could pose an issue for those who require control of a severe, chronic condition. Earlier studies offered contrasting opinions on the risks invovled when switching between generics. 

Michael Privitera, MD, professor at the University of Cincinnati Neuroscience Institute, and colleagues tested 2 generic lamotrigine products in a double-blind study, 1 of 3 studies in the FDA-funded EQUIGEN program. Lamotrigine is an antiepileptic indicated as adjunct in partial seizures, Lennox-Gastaut syndrome, or primary generalized tonic-clonic seizures in adults and children. It is also indicated for conversion to monotherapy in adults with partial seizures who are on carbamazepine, phenytoin, phenobarbital, primidone, or valproate as a single antiepileptic drug. 

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Researchers evaluated 35 adults with epilepsy who were currently taking lamotrigine and studied long-term dosing using 2 currently available generic antiepileptic drugs. Patients were switched from 1 generic to the other during the trial duration. The study included patient diaries, electronic medication monitoring and tablet counts to maintain adherence levels to almost 100%. The data showed as long as patients adhered to their treatments, the 2 generic products did not show any difference in their bioequivalence.

Some factors that may explain the previous inconsistencies include the "nocebo" effect, where both clinicians and patients expect the generic product to be inferior with a reduced therapeutic effect. A single-dose study of the same generic lamotrigine product is in progress to confirm the findings from this study.

Dr. Privitera stated,"[...] 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.”

For more information visit healthnews.uc.edu.

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