The U.S. Food and Drug Administration approved eslicarbazepine acetate, branded as Aptiom, as an add-on medication to reduce the frequency of partial seizures associated with epilepsy, the agency announced Friday. The drug is manufactured by Sunovion Pharmaceuticals in Marlborough, Mass.

According to the Centers for Disease Control and Prevention, each year there are 150,000 new cases of epilepsy, the neurological condition of recurring seizures. Seizures are episodes of abnormal electrical activity in the brain marked by generalized convulsions, unusual behavior, or repetitive limb movements, sometimes with loss of consciousness. Around 2.3 million people in the United States live with epilepsy. Partial seizures, a subtype of seizures which affect only part of the brain, make up the majority of new diagnoses of epilepsy. Although it is relatively uncommon, seizures could result in death.

Aptiom was shown to reduce the frequency of seizures in three randomized control trials testing the drug against a placebo. Participating subjects continued to use their previous anti-epileptic medications throughout the trials.

“Some patients with epilepsy do not achieve satisfactory seizure control from existing treatments,” said Dr. Eric Bastings, acting director of the Division of Neurology Products in the FDA. “It is important we continue to make new treatment options available to patients.”

The most common side effects experienced by trial subjects include dizziness, drowsiness, nausea, headache, double-vision, vomiting, fatigue, and loss of coordination. The FDA noted that taking esclicarbazepine acetate may cause suicidal thoughts or actions in a small number of people. The agency warns that anyone taking the drug who experiences unusual changes in mood — particularly worsening anxiety, depression, or thoughts about suicide — should contact their healthcare provider right away.

Esclicarbazepine acetate is the active metabolite of oxcarbazepine (Trileptal), an existing seizure medication. Manufacturers say that the new formulation may be an improvement over Trileptal, since it is metabolized more slowly and more tolerable.

Since 2009, Aptiom has been marketed in Europe as Zebinix. Currently, Aptiom is also in trials as a posisble treatment for bipolar disorder