Doctors have studied large numbers of patients to find out how well carbamazepine, the medicine in Tegretol-XR, controls seizures. They have reported that it completely controls partial seizures in about 70% of people just beginning their treatment, and that it completely controls tonic-clonic (grand mal) seizures in about 80%.

These promising results are not always matched in everyday life. Sometimes patients don't take all their medicine on time. Not everyone's seizures can be controlled at a dose that can be taken without side effects. Because of individual differences, there is no "best" amount for everyone. Adjustments are often needed to reduce seizures or side effects.

Many studies have compared carbamazepine with other seizure medicines, to see which medicine is best for people who have just begun treatment for epilepsy. On average, the results were about the same for carbamazepine as for several other seizure medicines that are often used.

Differences in side effects may be important in deciding which medicine is best for each person. In one study, people who took carbamazepine had fewer problems with side effects. Because some people do better with carbamazepine and others do better with something else, it's difficult to forecast the results in any given person. Some people have less trouble with side effects when they take Tegretol-XR than when they take other forms of carbamazepine, because the amount of medicine in the blood is more even throughout the day.

If seizures continue, the doctor probably will change the amount of Tegretol-XR prescribed. If that doesn't work, the next step may be either to prescribe a different seizure medicine by itself or to prescribe a combination of Tegretol-XR and another seizure medicine. Dilantin (phenytoin) is often used, but many other medicines are also available. No single combination is best for everyone.