New study reveals combining antiepileptic drugs most effective treatment

SAN ANTONIO (June 18, 2014) – A new study from The University of Texas Health Science Center at San Antonio finds that epilepsy patients respond better to antiepileptic drug combinations with different mechanism of action than to combinations of drugs with the same mechanism of action.

Mechanism of action is the specific biochemical interaction through which a drug produces its pharmacological effect. A mechanism of action can describe the specific molecular targets – such as an enzyme or receptor — to which the drug binds.

The study, “Effectiveness of Antiepileptic Drug Combination Therapy for Partial Onset Seizures Based on Mechanisms of Action,” was recently published online by JAMA Neurology. Jose E. Cavazos, M.D., Ph.D., a professor of neurology, pharmacology and physiology at the UT Health Science Center, and his colleagues began with a database of health insurance claims from more than 96 million Americans.

The investigators identified 8,600 patients who were recently diagnosed with epilepsy and had tried their first combination of antiepileptic drugs. They then studied the 8,600 patients’ records to determine the effectiveness of different drug combinations as well as hospitalizations, emergency room visits and total health costs.

“We found that combining antiepileptic drugs with different mechanisms of action had greater effectiveness as measured by longer treatment persistence and lower risk for hospitalization and ER visits. The research demonstrates that a rational approach for combining antiepileptic drugs is effective for the management for people with intractable epilepsy, which is a concern for about 3 million Americans,” said Dr. Cavazos, a co-director of the South Texas Comprehensive Epilepsy Center, a joint effort of UT Medicine San Antonio and the University Health System.

Antiepileptic drugs are among the top 10 most combined medicines, he said. “To our knowledge, this is the first proof on how to combine these medications. There has been a lot of experimenting on animals, but no randomized studies on humans,” Dr. Cavazos said. “It really took an analysis of a large sample to be able to select individuals who were taking their first or second drug combination.”

Dr. Cavazos said they took the data from health insurance companies who know two things: how much is spent on medical care and why the money is spent. “We applied a very scientific hypothesis to this data. We were able to define how long people refilled medications which tells us how long the medications kept working.”

They also looked at other health costs at the same time, Dr. Cavazos said. “We saw fewer emergency room visits and fewer hospitalizations. Using the best evidence we have available, we learned there are ways to combine medications for seizures to give patients the best quality of life that is possible.”

The study was an investigator-initiated hypothesis study with funding from Eisai, a pharmaceutical company, and third-party health claim data and statistical analysis. Dr. Cavazos did not receive financial compensation for developing, participating or being the senior author of this study.


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