Eslicarbazepine, brand name Zebenix®, a new epilepsy drug, was approved for sale in Europe. This drug, discovered in 1996, is chemically related to carbamazepine (Tegretol™) and oxcarbazepine (Trileptal™), but it may have fewer drug interactions than do carbamazepine and oxcarbazepine. Researchers in Sweden and Portugal reported results of a randomized controlled trial in 393 patients given either 0 (placebo), 400, 800 or 1200 mg of drug in a convenient single daily dose. Seizures were reduced by an average of 33% with the 800 and 1200 mg dose, significantly better than placebo. About 20-25% of the patients in the higher dosage groups discontinued treatment because of side effects, most commonly dizziness, sleepiness or headache. A second trial, performed in Poland, Hungary, Germany and Portugal enrolled about 400 patients, and found similar outcomes, with a 43% median seizure reduction rate at doses of 1200 mg per day. A third favorable trial brought the total of patients studied to 1049. The European authorities approved the medication as add-on treatment for adults with partial-onset seizures, with or without secondary generalization.