Despite the introduction of a large number of new drugs in the last decade, the proportion of people with epilepsy whose seizures are not controlled with currently available drugs has remained stable, at about 30%. Epilepsy is not considered drug-resistant or refractory until at least two anti-epileptic drugs (AEDs) have been tried over a period of two years, without significantly reducing seizures. The consensus among doctors is that the more drugs have been tried, the more unlikely another one is to work.

Professor Jacqueline French of the University of Pennsylvania, USA, investigated patient records from 155 people with refractory epilepsy aged 16 or over, treated at the Penn Epilepsy Center, Philadelphia. They all experienced at least one seizure a month (though some experienced more than 10), and had had epilepsy for between 6 and 54 years. Each of these people had previously tried an average of 5.8 different AEDs, though some had tried up to 15.

All patients received at least one new AED during the study, either in addition to their previous regimen, or replacing one of their previous drugs. Sixteen percent became seizure free for 12 months after a change, and 21% experienced less than half their usual number of seizures for 12 months after a change.

This is an unusual study, because it wasn't trying to show that one drug is better than another, just whether trying any new drug works or not. The analysis indicates that there's about a 15% chance of seizure freedom when another AED is tried. This suggests that keeping on trying new drugs is the best policy for gaining seizure freedom, and that improved control of seizures is possible even for patients who have not responded to several previous AEDs. This contradicts commonly accepted beliefs about refractory epilepsy, which says that there's no point in constantly trying new drugs as they have so little chance of making any difference.

This study, published in Nature Clinical Practice Neurology in July, is an exciting hint that received wisdom may be wrong regarding the treatment of refractory epilepsy. This study only had a short follow-up time (12 months) so it doesn't provide the final answer. However it does indicate that no patient should lose hope, and that their doctor should continue to try new combinations of AEDs until they find one that works.

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