Seizures are one of the most disturbing symptoms of brain tumors. The severity ranges from mild incidences of staring into space, to loss of consciousness with violent convulsions. They are not always associated with brain tumors, but some doctors prescribe antiepileptic drugs for all brain tumor patients anyway. Reference 2 discourages this practice because the drugs have serious side effects.
Antiepileptic drugs can be beneficial for brain tumor patients who have actually experienced a seizure. There are many types of brain tumors, and different types have different risks for seizure. Gliomas and meningiomas are the most common types in adults. Gliomas have many subtypes named after the cells they originate from. The grade of a glioma is a measure of how advanced it is. Low-grade gliomas can produce seizures in approximately 80 percent of cases. The risk of seizures depends on the size and location of the tumor. For low-grade gliomas, larger tumors are more likely to produce seizures.
For high-grade (more advanced and aggressive) gliomas, seizures are more likely with smaller tumors. I was surprised to read this. It appears that seizures can bring some good news, since they are more common with the less dangerous tumors.
Another surprising result reported in the medical literature is that switching from brand name to generic antiepileptic drugs is associated with a return of seizures. The University of Texas Health Science Center notes that several organizations support physician notification and patient consent before any change to generic drugs.
Drug interaction between antiepileptic drugs and chemotherapy agents are also a concern. Some cases of life-threatening complications have been reported. The antiepileptic drugs were developed for epilepsy, which affects 3.2 percent of adults over a lifetime and is usually caused by something other than brain tumors. However, some of the newer antiepileptic drugs introduced since the 1990's have fewer drug interactions and may be more beneficial for brain tumor patients.