Medical Conditions Related to Brain Injury: Seizures
Toxicity From Seizure Medication
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People taking anticonvulsants should have blood work done at regular intervals to determine whether there is too much or too little medication in his/her system. Most anti-seizure medication has a lab range doctors use as a reference point for this. To be accurate, blood work should be done at the same time of day under the same circumstances—for instance before eating breakfast and before taking morning meds. The goal is to ascertain what level of meds consistently remains in the system at the person’s lowest point.
It is important for the person or family member to also track the level each time a blood check is done because the lab range only represents a general guideline. Labs cannot take into account the individual response to a particular medication. Assume the range for Tegretol is 4 – 10. If the person’s blood work shows the medication level at 7, the medication is presumed to be at an effective level. However, this may not be the case. Some people can be toxic at 7. Others may need to be at a 9 to be protected from seizure. Only by tracking the number over time and correlating it to symptoms the person with brain injury presents, it is possible to determine what exact level keeps the person seizure-free with a minimum of side effects. When there is not sufficient medication in the system, the person is susceptible to seizure. When there is too much, he or she can become toxic, or plagued by undesirable side effects that impair a person’s ability to function.
Toxicity is an issue people on anti-seizure medication need to be aware of. Lab results are critical for creating a baseline, but they are not the best indicator of toxicity. Especially in emergency room settings or underserved areas where specialized care for seizure in brain injury is not available, signs of toxicity may be missed, especially if the patient’s blood levels show “in range.”
Some classic signs of toxicity are:
- Impaired walking
- Lack of usual coordination and balance
- Slow or slurred speech
- Inability to thinking clearly
- Sleepiness
- Jumpy eyes (Nystagmus)
- Blurry vision
These symptoms would, of course, have to be compared against the coordination/thinking level baseline of the person with brain injury. But in general, toxic patients appear drunk. They often say, “I feel like I’m in a fog.”
A good neurologist will recognize symptoms of toxicity if observed and will adjust medication accordingly. But physicians depend on family members and caregivers to note and report symptoms since they usually occur at home after medications have been taken for a while.
Also many other drugs such as antibiotics can interfere with protein binding that makes the seizure medication either more efficient or more toxic. No new drug or herbal remedy should be taken without first consulting a physician.
www.efa.org - Epilepsy Foundation site features current research, legislation and resources relating to epilepsy.
www.epilepsyga.org - Epilepsy Foundation of Georgia offers general information on seizures.
www.aan.com - Professional site of the American Academy of Neurology
Dr. Weissman is the current Medical Director of Day Rehabilitation and Rehabilitation Services of Children’s Healthcare of Atlanta at Egleston. She serves on the Board of Directors of the Brain Injury Resource Foundation. In addition, she is an Associate Professor of Pediatrics and Neurology at Emory University School of Medicine and a committee member of the American Society for Neurorehabilitation.