Oxcarbazepine (Trileptal)

When is oxcarbazepine used ?

Oxcarbazepine is used either alone or in combination with another seizure medicine to treat partial-onset seizures—that is, seizures that begin in a limited area of the brain. Sometimes these seizures spread throughout the brain or generalize.

Oxcarbazepine is not effective against absence or myoclonic seizures.

Besides its use in epilepsy, when else is oxcarbazepine used ?

Like carbamazepine, oxcarbazepine can also be used to treat a type of facial pain called trigeminal neuralgia (tic douloureux). It has also been helpful to stabilize mood in patients with bipolar disorder, formerly called manic-depression.

What are the most common side effects of oxcarbazepine ?

Most people who take oxcarbazepine have few or no side effects. Those that do experience them, tend to notice them particularly when first taking the medicine, and most often report:

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

Most of these side effects diminish and even disappear with time. However, if you have any of the above side effects and they do not go away or are particularly bothersome, call the doctor's office. Sometimes changing the amount of oxcarbazepine you take or how often you take it can help alleviate the side effects. However, no one should stop taking oxcarbazepine or change the amount they take without a doctor's guidance.

If you have just started taking oxcarbazepine (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 the effects of alcohol may be increased in people taking oxcarbazepine.

Allergic reactions

A small percentage of people taking oxcarbazepine 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 carbamazepine (Tegretol or Carbatrol), or other seizure medicines that are chemically related to oxcarbazepine. About 25% to 30% of patients who have had allergic reactions to carbamazepine will have the same type of reaction to oxcarbazepine.

What are some of the most serious side effects of oxcarbazepine ?

Very few people have serious reactions to oxcarbazepine. If you take it, you should be aware of them, however, so you and your family can recognize them. The following is a list of warning signs that may possibly be the start of a serious problem. If you notice any of these things, call your doctor right away:

  • Severe Skin reactions (see below)
  • Rash (possible allergic reaction)
  • 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 manufacturers of 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 Trileptal use. SJS and TEN may start with fever and flu-like symptoms followed by a rash, with or without ulcers of the mucous membranes, that quickly progresses to blisters that burn and are painful. If you notice a rash while taking oxcarbazepine, you should call your doctor immediately, and be prepared to describe it. Very rarely, these rashes are serious and with prompt attention and treatment, most potentially dangerous rashes will resolve completely.

Hyponatremia

In some patients, especially those taking higher doses of oxcarbazepine, 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.

Who should not take oxcarbazepine ?

The only people who definitely should not take oxcarbazepine are those who are allergic to it or any of its inactive ingredients. If you have absence or myoclonic seizures, oxcarbazepine will probably not be helpful, and may even be harmful, possibly increasing seizure frequency. People with kidney disorders need to be extra careful as oxcarbazepine may build up to a level that's too high. This is usually avoided by taking lower doses under the doctor’s direction.

Can oxcarbazepine be taken with other medicines ?

Sometimes one kind of medicine changes the way another kind of medicine works in the body. If two kinds of medicine affect each other, the doctor may prescribe something else or change the amount to be taken. Oxcarbazepine has very few problems of this kind. Oxcarbazepine does not seem to be affected by other medicines nor does it affect most other medicines. (See below for some exceptions.) This means that oxcarbazepine can be taken with most other medicines without difficulty.

One exception is that oxcarbazepine can make oral contraceptives (birth control pills), hormonal implants and injections less effective. To prevent pregnancy, a woman using these methods may need to use a different type of birth control, raise the dosage of the contraceptive or increase the frequency of the injection or implant. She sure to tell both the doctor prescribing contraception and the doctor prescribing oxcarbazepine about the other medicine so that the appropriate doses can be chosen. Oxcarbazepine does not affect barrier types of birth control, like condoms, non-hormonal IUDs, and diaphragms. Oxcarbazepine can cause the level of the seizure medicine phenytoin (Dilantin or Phenytek) to rise, so adjustments may be necessary if these medicines are used together.

If a woman takes oxcarbazepine during pregnancy, will it hurt the baby ?

In the United States, the Food and Drug Administration (FDA) assigns each medication to a Pregnancy Category according to whether it has been proven to be harmful in pregnancy. Oxcarbazepine is listed in Pregnancy Category C. This indicates that caution is advised, but the benefits of the medicine may outweigh the potential risks. Studies in animals have shown some harm to the baby, but there have been no good studies in women.

All women who are capable of becoming pregnant should take at least 0.4 mg (400 mcg) of the vitamin called folic acid every day because it helps to prevent specific birth defects called Neural Tube Defects. (The most well-known of these is spina bifida, in which the spinal cord is not completely enclosed.) Women with epilepsy should take between 1 and 4 mg of folic acid daily during their reproductive years. If the doctor thinks a woman is at especially high risk, the larger dose of folic acid—4 mg (4000 mcg) per day—may be recommended, beginning before the woman becomes pregnant.

Some babies born to mothers taking antiepileptic medications have had inadequate blood clotting within the first 24 hours after birth. It is often recommended that the mother be given 10 to 20 mg of vitamin K per day during the last month of pregnancy to prevent this problem.

About 50% of oxcarbazepine in the mother’s blood passes through breast milk, however how much of this actually enters the baby’s bloodstream is not known. Further, how oxcarbazepine affects the baby is unknown. That said, it is strongly felt by neurologists and epileptologists that the benefits of breastfeeding largely outweigh the risks of exposing the baby to antiepileptic medications, including oxcarbazepine. As a matter of fact, the American Academy of Neurology and the American Epilepsy Society both recommend breastfeeding in women with epilepsy.