Definition of drug‐resistant epilepsy: A reappraisal based on epilepsy types

Abstract

The prevalence of epilepsy is about seven cases per 1000 people worldwide. 1 The cornerstone of treatment of epilepsy is drug therapy with antiseizure medications (ASMs). 2 However, about one-third of patients with epilepsy (PWE) do not respond to drug therapy despite the use of appropriate ASMs. 3 On the other hand, epilepsy is not a single diagnostic entity; various brain disorders may cause epileptic seizures. The International League Against Epilepsy (ILAE) classifies the epilepsy types into focal and generalized epilepsies (in addition to the mixed types and unclassified epilepsies). 4 Any healthcare professional (HCP), who is dealing with PWE, should at least be able to recognize three general classes of epilepsies from

Drug resistance in epilepsy: A reappraisal of the definition is needed

“…As we cannot contemplate the same treatment strategy for patients with focal epilepsy and those with idiopathic generalized epilepsy (IGE), we also may not be able to apply the same definition of DRE for these two conditions (and for those with other syndromes). 5 In a recent study of 523 patients with focal epilepsy, 218 with IGE and 211 with other syndromes, the receiver operating characteristic curves of the number of appropriately chosen ASMs were acceptable indicators to anticipate DRE. The best cutoff point to anticipate DRE in focal epilepsy was at four ASMs, in IGE was at three ASMs, and in other syndromes was at four ASMs.…”

“…3 However, the denominator should have been the number of patients who were treated with the third ASM (not the total study cohort). 4,5 Furthermore, epilepsy is not a single diagnostic entity; various brain disorders may cause various types of epileptic seizures. As we cannot contemplate the same treatment strategy for patients with focal epilepsy and those with idiopathic generalized epilepsy (IGE), we also may not be able to apply the same definition of DRE for these two conditions (and for those with other syndromes).…”

“…The best cutoff point to anticipate DRE in focal epilepsy was at four ASMs, in IGE was at three ASMs, and in other syndromes was at four ASMs. 5 Additionally, factors such as patient satisfaction and the increased risks of morbidity and mortality (associated with continued seizures) should also be considered in the definition of DRE. 5 Finally, it is necessary to have high-quality epidemiological data to better define DRE.…”

The pharmacological treatment of epilepsy in adults

“…The definition of drug‐resistant epilepsy is based on the observation that the likelihood of seizure control declines with the number of failed ASM treatments. However, drug resistance does not exclude seizure freedom with further trials of ASMs 81–83 . If epilepsy surgery is not suitable, systematic trials of drug combinations should continue.…”

Nano‐delivery systems as a promising therapeutic potential for epilepsy: Current status and future perspectives

“…However, various biological factors have complicated the treatment of this disease and reduced the effectiveness of existing therapies 6,7 . The blood–brain barrier (BBB) is one of the most important barriers to the effectiveness of ASMs 8 . The endothelial cells lining the brain capillaries, along with other cells, including neurons, astrocytes, and pericytes, form a tight physical barrier that hampers the brain uptake of most unwanted substances from the blood (Figure 1).…”