Trileptal has now been in use since 1990, and it appears to be very safe. In the earliest tests, people who took it as their only medication or as an add-on to another seizure medicine were only slightly more likely to quit because of side effects than people who took a placebo (a pill with no active medicine) instead.

Some side effects of Trileptal that have been reported include:

• dizziness
• headache
• tiredness
• drowsiness
• double vision
• stomach upset
• loss of coordination

If you notice any of these problems, call the doctor's office. Sometimes the doctor can help by changing the amount of Trileptal you take or how you take it. Don't stop taking Trileptal or change the amount you take without the doctor's guidance.

If you have just started taking Trileptal (or have just started taking a larger amount), be careful doing anything that might be dangerous until you know whether you are feeling sleepy, dizzy, or uncoordinated. You should also be very cautious about drinking alcohol, because with Trileptal the effects of alcohol on the brain (such as tiredness, slurred speech, or unsteadiness) may be increased.

Allergic reactions
A small percentage of people taking Trileptal develop a rash within the first few weeks of taking it. If this happens, tell the doctor or nurse right away, to be sure that it's not the beginning of a serious problem. It's rare for the rash to be serious, but don't ignore it. It's often necessary to switch to a different seizure medicine.

Tell your doctor if you have ever had an allergic reaction to Tegretol or Carbatrol (carbamazepine), other seizure medicines that are chemically related to Trileptal. About 25% to 30% of patients who have had allergic reactions to carbamazepine will have the same type of reaction to Trileptal.

Long-term side effects
In some patients, especially those taking higher doses of Trileptal, the level of sodium (salt) in the blood may become low (a condition called hyponatremia). Usually this is not serious, but occasionally it may increase the number of seizures that you have or cause other problems such as tiredness or dizziness. Your doctor may want to check the amount of sodium in your blood to see if this is happening to you, especially if you are having nausea, a vaguely "unwell" feeling, headache, listlessness, or confusion.