Epilepsy - Medications

Tiagabine. Tiagabine (Gabitril) has properties similar to phenytoin and carbamazepine, and is also showing promise. Evidence has reported some significant side effects with its use, including dizziness, fatigue, agitation, and tremor. At least one study suggested that it has more adverse effects than lamotrigine and is not as well tolerated. In February 2005, the FDA issued a warning advising that tiagabine may cause seizures in patients without epilepsy. Tiagabine is only approved for use with other anti-epilepsy medicines to treat partial seizures in adults and children 12 years and older.

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Less Commonly Used AEDs

Felbamate. Felbamate (Felbatol) is an effective antiseizure drug. However, after reports of deaths from a serious blood condition known as aplastic anemia or from liver failure, felbamate is only recommended under certain circumstances. They include severe epilepsy, such as Lennox-Gastaut syndrome or as monotherapy for partial seizures in adults when other drugs fail.

Vigabatrin. Vigabatrin (Sabril) is a chemical called gamma-vinylGABA. It was designed to increase the brain levels of gamma aminobutyric acid (GABA), the enzyme that inhibits seizure activity. It has serious side effects, however, and is generally prescribed in the US in only certain cases, such as in low doses for patients with Lennox-Gastaut Syndrome. Overseas it is also used for partial seizures and as first line therapy in children with infantile spasms (West syndrome). Between 10% and 30% of people on long-term treatment have developed irreversible visual disturbances, including reductions in acuity and color vision. Men are at higher risk for this side effect than are women. Further studies are needed to determine the extent and severity of this complication, particularly in children. There is a slight risk for depression or psychosis when vigabatrin is used as add-on therapy, and particularly if the drug is administered too quickly. These risks are far lower if the drug is used as sole therapy.

Older Drugs. Some older but less effective drugs may still play a role against epilepsy:

Acetazolamide (Diamox) is sometimes used against common types of seizures, but patients quickly develop a tolerance for it. Some experts suggest it still may be useful when drug interactions are a problem, when a rapid effect is required, or when an additional drug is needed for a short time.
Trimethadione (Tridione) is effective for petit mal seizures, but has very serious side effects, and its use is severely limited.

Investigative Drugs

GABA Enhancers.Retigabine is an investigative GABA enhancer that may prove to be more effective than current AEDs with similar actions (vigabatrin, tiagabine, gabapentin and topiramate). It is currently in phase III trials for treatment of partial-onset seizures.

Other Investigative Anti-Epilepsy Drugs.Losigamone is a unique AED whose exact mechanism is unclear. In a well-conducted 2003 study, the drug appeared to be effective and safe for adults with partial epilepsy. Most side effects occurred within the first month and then subsided.

Drugsknown as AMPA receptor antagonists, for example, have anti-seizure properties and are under investigation. Talampanel is one such potentially effective AED and is currently in early trials.

Other anti-seizuredrugs being investigated include fluorofelbamate, safinamide, brivaracetam, and seletracetam.

Cannabinoids. Cannabinoids are compounds in marijuana (cannabis), which may have properties that protect nerve cells. In one 2003 report, people with epilepsy were twice as likely to use marijuana as the general public, with two thirds of them taking it because they believed it reduced their seizures. Other active users of marijuana reported no effect on seizures. No one has reported worse seizures from the drug. Animal studies further support some protection from cannabinoids against seizures. Clinical studies using humans have not been conducted.

Melatonin. Melatonin is a hormone found in the brain that is best known for its role in sleep. Some researchers believe that it might have properties that could benefit patients with epilepsy. Melatonin is a powerful hormone that can have major effects on all parts of the body. No one with epilepsy should experiment with thissupplement except as part of a clinical trial. Of note, in some studies, melatonin has been found to cause seizures in children who have existing neurologic problems.