How is refractory (drug-resistant) epilepsy defined?

• A. After trying several medications, seizures persist.
• B. Failure of two appropriate antiseizure medications at adequate doses to achieve seizure freedom.
• C. Not having access to medications.
• D. Having poor control on one medication.

Answer: (B)

Drug-resistant epilepsy means that two appropriately chosen, tolerated antiseizure medications have been tried at adequate doses but have not achieved sustained seizure freedom. This definition hinges on two solid trials: each medication must be suitable for the seizure type, taken at a therapeutic dose, and given long enough to judge effectiveness. When this level of response isn’t reached after those two proper trials, the epilepsy is considered drug-resistant, which prompts consideration of other treatment options such as surgery, neuromodulation, or dietary therapies.

Not having access to medications is a barrier to treatment, not a measure of drug resistance. Having poor control on one medication might be addressed by dose adjustment or trying a different drug, but it does not meet the threshold of two adequate trials. Saying that seizures persist after “several medications” is vague without specifying two proper trials at adequate doses that failed to achieve sustained seizure freedom.