Eslicarbazepine acetate add-on for drug-resistant focal epilepsy

Review question

This review is an update of a review first published 2011, and last updated in 2017.

We reviewed the evidence on the effectiveness and side effects of eslicarbazepine acetate when used as an add-on treatment for drug-resistant focal epilepsy.


Eslicarbazepine acetate is an antiepileptic medicine that can be added (called an 'add-on' treatment) to treat people who are taking other antiepileptic medicine but continue to have seizures (called drug-resistant epilepsy). This review looked at how well eslicarbazepine acetate worked when used as an add-on treatment and at some of the potential side effects of the medicine.

Study characteristics

The evidence is current to September 2020. We included seven clinical trials with 2185 participants aged two to 77 years. The included studies had different treatment periods of 12 to 18 weeks. All seven trials were randomized controlled trials, which means that people were randomly divided into groups and compared.

Key results

This review found that eslicarbazepine acetate was effective when used in combination with other medicines to reduce the number of seizures in adults with drug-resistant focal epilepsy. Eslicarbazepine acetate may also be effective in reducing seizure frequency in children with drug-resistant focal epilepsy. People who took eslicarbazepine acetate were more likely to have no seizures compared to people who took a placebo (a pretend tablet), but they were more likely to stop taking eslicarbazepine acetate because of side effects. These included dizziness, nausea (feeling sick), somnolence (feeling sleepy), vomiting (being sick) and diplopia (having double vision).

Quality of the evidence

Altogether the seven trials used good methods, but information was missing from the trials for between 10% and 45% of people taking the medicine in five trials of adults. This missing information may have introduced uncertainty into the results so the evidence in this review is of moderate quality. More research is needed to look at the long-term effects of eslicarbazepine acetate and to explore how well it works in children with epilepsy.

Authors' conclusions: 

ESL reduces seizure frequency when used as an add-on treatment for adults with drug-resistant focal epilepsy. The trials included in this review were of short-term duration. In addition, this update found that ESL may reduce seizure frequency in children from 6 to 18 years of age; however the results are inconclusive.

Read the full abstract...

This is an update of a review first published in 2011, and last updated in 2017.

Most people with epilepsy have a good prognosis, but up to 30% of people continue to have seizures despite several regimens of antiepileptic drugs. In this review, we summarized the current evidence regarding eslicarbazepine acetate (ESL) when used as an add-on treatment for drug-resistant focal epilepsy.


To evaluate the efficacy and tolerability of ESL when used as an add-on treatment for people with drug-resistant focal epilepsy.

Search strategy: 

For this update, we searched the following databases on 10 September 2020: Cochrane Register of Studies (CRS Web) and MEDLINE (Ovid). CRS Web includes randomized or quasi-randomized, controlled trials from Specialized Registers of Cochrane Review Groups including Epilepsy, CENTRAL, PubMed, Embase, and the WHO ICTRP. There were no language restrictions. We reviewed the reference lists of retrieved studies and contacted the manufacturers of ESL and experts in the field for information about any unpublished or ongoing studies.

Selection criteria: 

Randomized placebo-controlled double-blind add-on trials of ESL in people with drug-resistant focal epilepsy.

Data collection and analysis: 

Two review authors independently selected trials for inclusion and extracted data. Outcomes investigated included 50% or greater reduction in seizure frequency, seizure freedom, treatment withdrawal, adverse effects and drug interactions. Primary analyses were by intention to treat (ITT). The dose-response relationship was evaluated in regression models.

Main results: 

We included seven trials (2185 participants, aged 2 to 77 years), which were at low or unclear risk of bias apart from a high risk of attrition bias; all studies were funded by the pharmaceutical company, BIAL.

The overall risk ratio (RR) for 50% or greater reduction in seizure frequency was 1.57 (95% confidence interval (CI) 1.34 to 1.83). For adults, the RR was 1.71 (95% CI 1.42 to 2.05; 5 studies, 1799 participants; moderate-certainty evidence); for children aged six to 18 years, the RR was 1.35 (95% CI 0.98 to 1.87; 2 studies, 322 participants; moderate-certainty evidence). Dose regression analysis showed evidence that ESL reduced seizure frequency with an increase in efficacy with increasing doses of ESL. ESL was associated with seizure freedom (RR 3.16, 95% CI 1.73 to 5.78; 6 studies, 1922 participants; moderate-certainty evidence). Participants were more likely to have ESL withdrawn for adverse effects (RR 2.72, 95% CI 1.66 to 4.46; 7 studies, 2185 participants; moderate-certainty evidence), but not for any reason (RR 1.25, 95% CI 0.93 to 1.70; 7 studies, 2185 participants; moderate-certainty evidence). The following adverse effects were associated with ESL: dizziness (RR 2.77, 99% CI 1.85 to 4.15); nausea (RR 2.55, 99% CI 1.39 to 4.67); somnolence (RR 1.75, 99% CI 1.18 to 2.61); diplopia (RR 4.07, 99% CI 1.86 to 8.89); and vomiting (RR 2.37, 99% CI 1.19 to 4.74). Overall, the certainty of the evidence was moderate due to a high discontinuation rate in studies of adults.