No studies have been performed evaluating the effectiveness of a single medication as initial treatment of the seizures in a child with LGS. Historically, valproate or valproic acid has been considered the first line treatment option. From a practical point, often by the time the physician makes the diagnosis of LGS, the child has already been diagnosed with epilepsy and treatment initiated. After the diagnosis of LGS is made, the treatment may need to be refined so that effective therapies are utilized and any drugs which may potentially worsen the seizure control are eliminated.

Valproate can be effective against multiple seizure types seen in a child with LGS. It is available in formulations that allow it to be dosed for infants, children and adolescents. In general, valproate is well tolerated, but some children may have stomach upset, sedation, or increased appetite. Rarely, especially in children below age 2 years, valproate may cause serious liver failure, potentially resulting in death. In light of this rare side effect, if valproate is used in young children, careful attention to symptoms of potential liver toxicity are important for the parents to be aware of so they can communicate them to the physician at the earliest occurrence. Additionally, in light of this possible side effect, some physicians may not wish to use this in a child that has LGS and who they have a concern about an underlying metabolic cause, as this may increase the risk for the hepatic toxicity.

Benzodiazepines, primarily clonazepam, have also been used historically as a treatment for LGS. These are primarily helpful for the convulsive and the myoclonic seizures. The side effects of clonazepam include behavioral symptoms such as increased activity and changes in mood. Other side effects include sedation, drooling and worsening of motor coordination. Additionally, the effectiveness of clonazepam typically decreases over time making this primarily useful for a short term seizure control.

Several newer seizure medications have undergone detailed evaluation in the treatment of LGS. These include

• felbamate,
• lamotrigine,
• topiramate,
• rufinamide, and
• clobazam.

These medications are all unique as they are the only one’s that have undergone the detailed evaluation as to how well they work in children and adults with LGS, and to describe their side effect profile in this population. As such, these medications should be used earlier in the treatment in LGS. Many are often combined with valproate or valproic acid.

Felbamate was found to be an effective medication, and many patients had a dramatic improvement in atonic (drop) seizures and convulsive seizures, along with other seizure types. Common side effects include decreased appetite, insomnia (difficulty falling asleep) and irritability. However, most of these can be managed. However, rare children may experience liver toxicity, and rare adolescent and adults may experience a toxicity in the bone marrow (blood forming elements in the body) resulting in serious, potentially even fatal complications. This has dramatically restricted the use of felbamate. In children and adults having atonic seizures resistant to other therapies, felbamate still remains a good treatment option. As with all treatments, the physician and family should balance the potential benefits of the medications vs. the risk of the medications and the risk of continuing seizures.

Lamotrigine was the next medication that was thoroughly evaluated in LGS. This medication helps improve convulsive seizures, and may result in improvements in behavior, coordination and speech. This medication has complicated drug interactions with other seizure medications, and is slow to initiate and achieve an effective dose, limiting it’s usefulness in children who are having frequent daily seizures. It often may take 8-12 weeks or longer to achieve a full dose of this medication in a child. In general, this medication is well tolerated but the primary concern is the risk of serious rash, especially if the medication is initiated too quickly. Rash appears more likely in children who are also taking valproate. However, this should not discourage a clinician from utilizing lamotrigine with valproate, as this appears to be a good combination for treating the seizures associated with LGS. Doctors and families should be aware that valproate decreases the metabolism and excretion of lamotrigine, so lamotrigine blood levels typically increase significantly when valproate is added. This can lead to drug side effects, so the clinical condition (and sometimes blood levels) should be monitored. When lamotrigine is being initiated in child with LGS, if the child develops a rash, the family should discontinue the medication and contact the physician immediately. The common side effects when using lamotrigine are vomiting, nausea and ataxia (staggering gait).

Topiramate was also found to be effective in treating the convulsive seizures in Lennox-Gastaut Syndrome. This medication may decrease the child’s appetite and cause sedation. In some children there may be impairment with their developmental progress. This should be monitored in a child when initiating this medication. A more common side effect is decreased sweating, making it difficult or impossible for the child to play outside when it is warm. This occurs more frequently in infants and young children and less often in adolescents and adults. Topiramate occasionally leads to kidney stones, which can be quite painful and result in increase in seizure frequency in children (who may not be able to report the pain correctly), and very rarely to glaucoma, producing eye pain or a change in vision (decreased ability to see items at a distance).

Rufinamide is the newest medication to be approved in the United States for the treatment of LGS. This drug is effective in treating atonic seizures (drop attacks) and convulsive seizures. Rufinamide does not appear to worsen other seizure types. A recent study showed benefit for partial seizures. Common side effects include nausea or vomiting, and sedation. These can be lessened by slowly initiating the medication. Rarely, a serious rash may occur on this medication, so like any medication, if a rash occurs during the first several weeks or months on this medication, the pediatric neurologists’ office should be contacted immediately.

Clobazam, a benzodiazepine, is currently undergoing evaluation in the United States for treatment of drop attacks associated with Lennox-Gastaut Syndrome. This medication has been available for many years in almost every other country for use of drop attacks and convulsive seizures. It appears better tolerated than clonazepam, and its beneficial effects may wear off less often than with other benzodiazepines. Common side effects of clobazam include sedation or changes in behavior and mood. If these side effects occur, they are usually noted within the first weeks.

Other medications have been less well studied but have been used in treating children, adolescents and adults with LGS. These medications include

• ethosuximide,
• vigabatrin,
• zonisamide, and
• levetiracetam.

Some medications may worsen the frequency of seizures. While this is a rare event, it can be serious and should not be overlooked. How this occurs is poorly understood. Additionally, in some children these medications may be useful in treating certain seizure types. As such, when these are used, the physician should be aware of the rare potential to worsen seizure types, and if this occurs, be prepared to withdraw the medication (see table below for list of medications and seizure type which may be worsened).

Author: James Wheless, M.D.
Topic Editor: Robert Fisher, M.D., Ph.D.
Last Reviewed: 8/7/09