Serious side effects of carbamazepine are rare. It is important to be aware of possible reactions and what to do if they happen. Only a very small number of people have died from them.
- Read the package insert for a complete list of all reactions to carbamazepine.
- Call your provider's office right away if any of these problems occur.
Allergic reactions: About 5 to 10% of people who take carbamazepine have a red rash within in the first month of taking it. If this happens, tell your health care provider to be sure that it's not the beginning of a serious problem.
- Tell your provider if you have had a rash to oxcarbazepine or eslicarbazepine or any similar medications in the past. You could have a similar reaction to carbamazepine.
Severe skin reactions: Carbamazepine can cause rare but serious skin reactions, such as Stevens-Johnson Syndrome (SJS) and toxic epidermal necrolysis (TEN). These conditions may start with a fever and flu-like symptoms. Then a rash develops. Ulcers or lesions of the mucous membranes may be seen and develop into painful blisters.
- Report any fever or rash to a health care provider as this can be a life-threatening condition.
- These types of skin reactions happen most commonly in the second or third week after starting the medicine. Though it can happen at other times too.
- Serious skin rashes are more common in people with a particular gene called “HLA-B*1502.” (An allele is a form of a gene that is found on a chromosome. Alleles are involved in deciding whether certain traits passed on from a parent to a child will occur. The tendency to severe drug reactions can be one of these traits.)
- This gene is found in ancestry or family lines from broad areas of Asia including South Asian Indians. People who are Chinese, Thai, Filipino, Malaysian, and Korean may have an increased risk for these skin reactions with carbamazepine.
- People at risk should be tested for the HLA-B*1502 allele before starting carbamazepine. If you test positive, you should avoid using this medicine unless your provider and you decide the benefits are worth the risks.
Blood disorders: Certain changes in blood cells may happen and lead to serious problems. Only 1 in 30,000 people who take carbamazepine will develop one of these blood disorders. This risk is higher than the risk for people who do not take carbamazepine. Some symptoms of a blood disorder may include:
- Bruising easily
- Nosebleeds or other unusual bleeding
- Sore throat
- Sores in the mouth
- Tiny red spots on the skin
Blood tests are usually done before starting carbamazepine and again while taking it. These tests look for any changes that happen while on this medicine. Some people may have some small changes in their blood that go away on their own.
If you notice any of these symptoms, call your health care provider right away. Do not stop taking carbamazepine without your doctor's advice.
Liver problems: Liver problems are another serious disorder that occurs in a few people who take carbamazepine. Some symptoms may include:
- Black or pale color of bowel movements
- Loss of appetite
- Nausea, upset stomach, vomiting
- Stomach pain
- Yellow eyes or skin
Tell your health care provider right away if you notice any of these problems. Do not stop taking carbamazepine without your doctor's advice.
Suicidal thoughts and behavior: In 2008, the Food and Drug Administration (FDA) reviewed data from drug studies that showed a possible relationship between many seizure medicines and suicidal thoughts and behavior. Together, these thoughts and behavior are called suicidality. According to the FDA’s Alert, among the patients with epilepsy in these drug studies, more had symptoms of suicidality than people taking a placebo or inactive substance - 3.5 of 1,000 people taking a seizure medicine had suicidality compared to 1 of 1,000 people taking a placebo.
- Taking seizure medicines may increase the risk of having suicidal thoughts or actions.
- Do not make any changes to the medicines without first talking to your prescribing health care provider.
- 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
- Contact your health care provider before stopping any seizure meicine. This could possibly lead to worsening of seizure and mood.