Most people who take oxcarbazepine have no side effects or mild side effects that go away with no lasting harm. But a few people have serious reactions. Tell your doctor if you have ever had an allergic reaction to Tegretol or Carbatrol (carbamazepine), other seizure medicines that are chemically related to oxcarbazepine.

About 25% to 30% of patients who have had allergic reactions to carbamazepine will experience the same type of reaction to oxcarbazepine.

Here's a list of symptoms that may possibly be the start of a serious problem. If you notice any of these symptoms, call your doctor right away:

• Severe Skin reactions (see below)
• Rash (possible allergic reaction)
• Other severe allergic reactions
• Swelling of the throat, lips and eyelids, which could occur after the first or later doses. These reactions can be life-threatening, and people who have had these reactions should not take the drug again.
• Vomiting
• Increased seizures
• Frequent headaches or a headache that doesn't go away
• Sluggishness
• Confusion

Severe Skin Reactions
As of April 19, 2005 the FDA and Novartis pharmaceuticals (the manufacturer of the brand name version of oxcarbazepine - Trileptal) issued a new warning regarding oxcarbazepine. Serious dermatological reactions, including Stevens-Johnson syndrome (SJS) and toxic epidermal necrolysis (TEN), have been reported in both children and adults in association with oxcarbazepine use. SJS and TEN may start with fever and flu-like symptoms. Then, a rash develops, with or without ulcers of the mucous membranes, that quickly progresses to blisters that burn and are painful.

The most common time of onset after first dosage of oxcarbazepine was 19 days. Such serious skin reactions may be life-threatening, and some patients have required hospitalization with very rare reports of fatal outcome. Therefore, if you have any skin reactions upon taking oxcarbazepine, you should seek immediate medical attention.

Hyponatremia
The last five symptoms in this list could occur if you have a low level of sodium in your blood, a condition called hyponatremia. This condition has been reported in about 2.5% of patients taking oxcarbazepine. It has occurred most often during the first 3 months of treatment, but in some cases it has been discovered much later. Usually it is not serious but it could lead to coma, more frequent seizures, or other major problems. Often there are no apparent symptoms, so your doctor may want to check your blood to see if this is happening to you even if you are feeling well.

One other warning—it's not unusual for oxcarbazepine to make people feel sleepy or uncoordinated. If you've just started taking oxcarbazepine or have just had your dosage increased, you should be careful about things that could be dangerous (like driving or operating machinery) until you know how it will affect you.

On July 10, 2008, an advisory panel was convened by the Food and Drug Administration (FDA) to review data that the FDA had previously collected from drug studies showing an association between many of the antiepileptic drugs (AEDs) and suicidal ideation and behavior, which together are called suicidality. According to the FDA’s Alert, among the patients with epilepsy in these drug studies, 1 out of 1000 people taking the placebo (inactive substance) showed suicidality compared to approximately 3.5 out of 1000 people who took an AED. The FDA advisory panel voted to accept the FDA's data at its meeting on July 10. The FDA has provided the following information for patients, family members, and caregivers at www.fda.gov/cder/drug/InfoSheets/HCP/antiepilepticsHCP.htm.

• Taking antiepileptic medicines may increase the risk of having suicidal thoughts or actions;
• Do not make any changes to the medication regimen without first talking with the responsible healthcare professional;
• Pay close attention to any day-to-day changes in mood, behavior and actions. These changes can happen very quickly so it is important to be mindful of any sudden differences.
• Be aware of common warning signs that might be a signal for risk of suicide. Some of these are:
  • Talking or thinking about wanting to hurt yourself or end your life
  • Withdrawing from friends and family
  • Becoming depressed or having your depression get worse
  • Becoming preoccupied with death and dying
  • Giving away prized possessions

We again urge patients and families to contact their doctor before stopping an epilepsy medication because this may possibly lead to seizures and worsening of mood.

Reviewed July 2008 by Steven C. Schachter, MD, epilepsy.com Editorial Board.