Epilepsy - Medications

A rash occurs in 5% of patients; it may disappear in some patients who continue taking the drug, but in rare cases it can become very severe. The risk of the rash increases if the drug is started at too high a dose or if the patient is also taking valproic acid. (Serious rash is more common in young children who take the drug than it is in adults.) Other side effects may include nausea, dizziness, blurred vision, headache, and sleepiness. Some patients report severe insomnia. A rare but serious side effect is anticonvulsant hypersensitivity syndrome, which is characterized by fever, skin eruptions, abnormal lymph nodes, and liver damage.

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Gabapentin. Gabapentin (Neurontin) is an effective add-on drug for controlling complex partial seizures and secondarily generalized partial seizures and is approved for adults and children with these seizures. In a 2002 analysis of current evidence, it achieved response rates in patients with resistant partial epilepsy that were as high as 28% at high doses. It is not at all useful for generalized petit mal seizures.

Its toxicity is low and side effects include sleepiness, headache, fatigue, and dizziness. Some weight gain has been reported. Gabapentin has no significant interactive effects when taken with other drugs. It has the added advantage of improving mood, which is independent from its effect on seizure control. Children may experience hyperactivity or aggressive behavior. Long-term adverse effects are still unknown.

Pregabalin. Pregabalin (Lyrica) is similar to gabapentin. In 2005, it was approved as add-on therapy to treat partial-onset seizures in adults with epilepsy. In clinical trials, half of the patients who received pregabalin experienced a 50% reduction in seizure frequency. Side effects may include dizziness, sleepiness, dry mouth, swelling in hands and feet, blurred vision, weight gain, and trouble concentrating

Topiramate. Topiramate (Topamax) is similar to phenytoin and carbamazepine and is effective and safe for a wide variety of seizures in adults and children. It is approved as add-on therapy for patients 2 years and older with generalized tonic-clonic seizures, partial-onset seizures, or seizures associated with Lennox-Gastaut syndrome. It is also approved as single therapy for patients 10 years and older with tonic-clonic seizures or partial-onset seizures. Studies have shown a 34 - 87% reduction in seizure frequency with some patients becoming seizure-free. Topiramate may have fewer interactions with oral contraceptives than other AEDs.