WARNING: SERIOUS AND SOMETIMES FATAL RASHES HAVE RARELY OCCURRED WITH THE USE OF THIS MEDICINE. The risk of serious rash may be greater in children younger than 16 years old than in adults. Although it has not been proven, the risk may also be greater if you start taking this medicine at a higher than recommended dose, if you take more than the recommended dose during treatment, or if you also take a medicine called valproate (eg, valproic acid, divalproex sodium). Most of the serious rashes that have occurred with the use of this medicine developed within the first 2 to 8 weeks of treatment. However, serious rashes have also occurred in patients who have used this medicine for a longer period of time. Contact your doctor at once if you develop rash symptoms, including red, swollen, blistered, or peeling skin. Treatment with this medicine should be stopped if rash occurs, unless it is clearly determined that the medicine did not cause the rash. Even if this medicine is stopped, a rash caused by this medicine may still become life-threatening or cause other serious side effects (eg, permanent scarring). SOME MEDICINES MAY INTERACT with this medicine. TELL YOUR HEALTH CARE PROVIDER if you are taking any other medicines, especially any of the following: carbamazepine, valproate (eg, valproic acid, divalproex sodium), estrogens, phenobarbital, phenytoin, primidone, rifampin, succinimides (eg, methsuximide), or hormonal contraceptives (eg, birth control pills). This may not be a complete list of all interactions that may occur. Ask your health care provider if this medicine may interact with other medicines you take. DO NOT START OR STOP any medicine without doctor or pharmacist approval. Inform your doctor of any other medical conditions, including liver, kidney, or heart problems; certain blood problems (eg, thalassemia); a skin rash; allergies, especially to other anti-seizure medicines; pregnancy; or breast-feeding. Tell your doctor if you have a history of developing a skin rash from taking this medicine or any other medicines to treat seizures; mental or mood problems (eg, depression); or suicidal thoughts or attempts. Tell your doctor if you receive dialysis treatments. This medicine should not be used in CHILDREN younger than 13 years old; safety and effectiveness in these children have not been confirmed. Contact your doctor or pharmacist if you have any questions or concerns about using this medicine.