Potentially life-threatening reactions to carbamazepine involve aplastic anemia, toxic hepatitis, pancreatitis and skin reactions, specifically Stevens Johnson syndrome and toxic epidermal necrolysis.

About 1 in 30,000 people who take carbamazepine will develop serious blood disorders. Baseline blood and platelet counts should be obtained and repeated early in the course of therapy. Generally, discontinuation of carbamazepine is not necessary unless blood counts are significantly reduced or leukopenia persists. (Up to 10% of patients have a leukopenia that reverses within 1-2 weeks.) Patients should be told to report easy bruising, fever, or infections.

Renal and hepatic function tests also can be performed before treatment and repeated later if clinically indicated. Patients should be advised to report possible symptoms of hepatitis, including:

• yellow eyes or skin
• loss of appetite
• upset stomach with vomiting
• black or pale bowel movements

On December 12, 2007, the Food and Drug Administration informed healthcare professionals that dangerous or even fatal skin reactions (Stevens Johnson syndrome and toxic epidermal necrolysis), that can be caused by carbamazepine therapy, are significantly more common in patients with a particular human leukocyte antigen (HLA) allele, HLA-B*1502. This allele occurs almost exclusively in patients with ancestry across broad areas of Asia, including South Asian Indians. Patients with ancestry from areas in which HLA-B*1502 is present should be screened for the HLA-B*1502 allele before starting treatment with carbamazepine. If these individuals test positive, carbamazepine should not be started unless the expected benefit clearly outweighs the increased risk of serious skin reactions. Patients who have been taking carbamazepine for more than a few months without developing skin reactions are at low risk of these events ever developing from carbamazepine. This is true for patients of any ethnicity or genotype, including patients positive for HLA-B*1502. (source: http://www.fda.gov/medwatch/safety/2007/safety07.htm#carbamazepine)

• Further Information for Healthcare Professionals Related to this Topic
• FDA Drug Information Page for Carbamazepine

If you believe that you have experienced a serious side effect from a medication, you or your physician can bring it to the attention of the FDA, through their MedWatch program, by completing an adverse event report form (http://www.fda.gov/medwatch/getforms.htm). MedWatch is the FDA's program for reporting serious reactions and problems with medical products, such as drugs and medical devices. (http://www.fda.gov/medwatch/getforms.htm.) To learn more about the Medwatch program go to: http://www.fda.gov/medwatch/report/consumer/consumer.htm

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.