Several anticonvulsant medications are effective in treating and preventing the different phases of bipolar disorder, though they are usually more effective in mania than in the depressed phase. They were first introduced into the treatment of bipolar disorder in the 1970s as an answer to rapid cycling – a form of bipolar disorder in which the person with the illness experiences several cycles a year from mania into depression and back. The anticonvulsants are still the treatment of choice for rapid cycling, but they can also be very effective when the course of illness is not disturbed in this way. The most common and effective anticonvulsants are valproate or valproic acid (brand name Depakote), carbamazepine (brand name Tegretol) and oxcarbazepine (brand name Trileptal).
Another anticonvulsant is sometimes used, but should be reserved for a special purpose; the anticonvulsant is lamotrigine (brand name Lamictal) and its special value is in helping to lift people with bipolar disorder out of a treatment-resistant episode of depression. Given in too high a dose, however, it can provoke the appearance of manic symptoms. It can also, rarely, cause a serious, potentially fatal, skin condition known as Stevens-Johnson syndrome, so it must be prescribed with great care by doctors who are familiar with its use and the dose must be increased quite slowly. If you are taking Lamictal and you develop a painful rash you should let your doctor or treatment team know about it immediately.
Side effects of any of these anticonvulsants include sedation, stomach upset, tremor, headache, dizziness and unsteadiness. Weight gain is more common with Depakote. Tegretol carries a remote chance of a catastrophic drop in a person’s white blood cell count, which is dangerous. Both Tegretol and Trileptal can lead to a drop in the amount of sodium in your blood, which can have negative consequences, and may mean that the medication has to be discontinued.
We know with some accuracy the blood level of the different anticonvulsants that is likely to be effective in treating bipolar disorder. A complication in the use of these medications, however, is that they are excreted through the liver, and your liver will get better and better at eliminating the drug from your body. This means that, as you are getting started on the medication, though you may have an adequate blood level this week, next week it may be too low. Your doctor will have to keep ordering blood tests for a few weeks and adjusting your dose of the medication, until the level finally reaches a plateau and remains steady.