Drug-Resistant Epilepsy: Still Having Seizures After 2 Medicines?
By the time you have tried a second or third seizure medicine, it is easy to feel like you are running out of road. The medical term for this situation, drug-resistant epilepsy, can sound final. It is not. It is a signal to change strategy, and it is the point at which specialist care and research studies most often come into the picture.
Key takeaways
Drug-resistant epilepsy means two well-chosen, tolerated medicines at adequate doses have not produced lasting seizure freedom.
The ILAE estimates about one-third of people with epilepsy continue to have seizures despite medication.
Chances with each new medicine are lower, but not zero. In one long-term study, about 1 in 4 people who tried a third regimen became seizure-free.
Specialist options include surgery evaluation, neurostimulation, dietary therapy and clinical trials.
What "drug-resistant" actually means
The International League Against Epilepsy (ILAE) defines drug-resistant epilepsy as failure of two tolerated, appropriately chosen and used antiseizure medicine schedules, alone or in combination, to achieve sustained seizure freedom. Three parts of that definition matter:
Appropriately chosen: the medicine has to suit your seizure type. A medicine that was a poor match for your seizures does not count as a real trial.
Tolerated and at an adequate dose: stopping a medicine early because of side effects is different from it not working.
Sustained freedom: the goal is no seizures, not just fewer.
This is why an epilepsy specialist will review your full history before deciding the label fits. See why seizure type matters.
Your chances do not stop at two
An often-quoted statistic suggests the odds of seizure freedom fall to almost nothing after two medicines. A closer look at the data tells a more hopeful and more accurate story. In a 30-year study of people with newly diagnosed epilepsy, researchers found that among those who went on to try a third medicine regimen, about 23.6% became seizure-free, and some people responded even on a fourth, fifth or sixth, according to an ILAE analysis of the findings. The chances drop with each step, which is exactly why specialists add other approaches alongside medicine changes rather than instead of them.
What an epilepsy specialist reviews
Your seizure types, how often they happen and what they look like
Every medicine you have tried, the doses and why each one stopped
Side effects and how well you tolerate your current medicines
Video-EEG and MRI results, or the need for them
Sleep, mood, other health conditions and other medicines
An accurate seizure diary makes this review much more productive.
Options specialists may discuss
A different medicine combination: choosing a medicine that works in a different way from the ones already tried.
Epilepsy surgery evaluation: for focal epilepsy with a clear starting point, removing or disconnecting that area can lead to seizure freedom for some people.
Neurostimulation devices: implanted devices that stimulate a nerve or brain area to reduce seizures, such as vagus nerve stimulation, responsive neurostimulation or deep brain stimulation.
Dietary therapy: medically supervised diets such as the ketogenic or modified Atkins diet.
Clinical trials: access to investigational medicines under close study monitoring, with no guarantee of benefit.
Two or more seizure medicines tried, still having seizures? See whether a research study may fit.
Research designed for this exact situation
Both studies below require participants to have tried at least two seizure medicines without lasting seizure freedom, and to be taking 1 to 3 medicines now. They test XEN1101 (azetukalner), an investigational medicine, added to those current medicines and compared with placebo.
Study snapshot: two Phase 3 epilepsy studies
What is being studied
XEN1101 (azetukalner), an investigational once-daily capsule taken with the evening meal. It is designed to act on Kv7 potassium channels, which help calm overactive electrical signals in brain cells.
How it is tested
Added to a person's current seizure medicines and compared with placebo in a randomized, double-blind design. A baseline period of up to about 9.5 weeks is followed by 12 weeks of blinded treatment.
X-ACKT (NCT05667142)
People aged 12 and older with generalized epilepsy who have primary generalized tonic-clonic seizures, have tried at least two seizure medicines, and currently take 1 to 3.
X-TOLE3 (NCT05716100)
Adults aged 18 and older with focal epilepsy diagnosed at least two years ago, who have tried at least two seizure medicines and currently take 1 to 3.
After the blinded period
People who complete the 12 weeks may be able to join a separate open-label extension study, where everyone receives XEN1101.
Where
X-ACKT has dozens of research sites across the U.S., including epilepsy centers in Boston, Philadelphia, Atlanta, Houston, Cleveland, Seattle and Los Angeles. The study team can tell you the nearest site for either study.
Never stop seizure medicine on your own
Stopping or changing antiseizure medicine suddenly can trigger severe seizures, including status epilepticus. Make any change only with your neurologist.
Still sorting out why seizures keep happening? Start with breakthrough seizures and common triggers.
Frequently asked questions
What is the definition of drug-resistant epilepsy?
According to the ILAE, it is epilepsy in which two tolerated, appropriately chosen and used antiseizure medicine schedules, alone or combined, have not achieved sustained seizure freedom.
Is drug-resistant epilepsy the same as refractory epilepsy?
The terms are often used interchangeably. Drug-resistant epilepsy is the term preferred by the ILAE.
Can a third seizure medicine still work?
Yes, for some people. In a long-term study, about 23.6% of people who tried a third medicine regimen became seizure-free. The chances are lower than with the first medicine, which is why specialists also consider other options.
Are clinical trials only for people with no other options?
No. Trials are one option among several, and they have specific criteria. The X-ACKT and X-TOLE3 studies enroll people who have tried at least two seizure medicines and currently take 1 to 3.