Carbamazepine may cause life-threatening allergic reactions called Stevens-Johnson syndrome (SJS) or toxic epidermal necrolysis (TEN). These allergic reactions may cause severe damage to the skin and internal organs. The risk of SJS or TEN is highest in people of Asian ancestry who have a genetic (inherited) risk factor. If you are Asian, your doctor will usually order a test to see if you have the genetic risk factor before prescribing carbamazepine. If you do have this risk factor, your doctor will probably prescribe another medication that is less likely to cause SJS or TEN. If you do not have this genetic risk factor, your doctor may prescribe carbamazepine, but there is still a slight risk that you will develop SJS or TEN. Call your doctor immediately if you develop a rash, blisters, or a fever during your treatment with carbamazepine.
Stevens-Johnson syndrome or toxic epidermal necrolysis usually occurs during the first few months of treatment with carbamazepine. If you have taken carbamazepine for several months or longer, you probably will not need to be tested, even if you are Asian.
Carbamazepine may decrease the number of blood cells produced by your body. In rare cases, the number of blood cells may decrease enough to cause serious or life-threatening health problems. Tell your doctor if you have ever had a decreased number of blood cells, especially if it was caused by another medication. If you experience any of the following symptoms, call your doctor immediately: sore throat, fever, chills, or other signs of infection; unusual bleeding or bruising; tiny purple dots or spots on the skin; mouth sores; or rash.
Keep all appointments with your doctor and the laboratory. Your doctor will order certain lab tests before and during your treatment to check your body's response to carbamazepine.
Your doctor or pharmacist will give you the manufacturer's patient information sheet (Medication Guide) when you begin treatment with carbamazepine and each time you refill your prescription. Read the information carefully and ask your doctor or pharmacist if you have any questions. You can also visit the Food and Drug Administration (FDA) website (http://www.fda.gov/Drugs
) or the manufacturer's website to obtain the Medication Guide.