Randomized, controlled studies comparing Neurontin (brand name version of gabapentin) and placebo used as add-on therapy have found that Neurontin reduces seizure frequency by at least half in about 12% more patients (Cramer et al. 2001). Side effects were only a little more troublesome than with the placebo and often went away without stopping the medication.

A study of add-on therapy in children aged 3 to 12 years had fairly similar results, with the greatest improvement reported for those with complex partial seizures and secondarily generalized seizures (Appleton et al. 1999).

No single combination of antiepileptic medications is perfect for everyone. Sometimes, a series of combinations must be tried before finding what is best for the individual patient. Because gabapentin generally does not interact with other medications, no adjustments are needed when it is used in combination with other seizure medicines. Gabapentin is a good choice for patients (such as many elderly people with epilepsy) who need to take medicine for other disorders.

Studies have also looked at the effectiveness of Neurontin (brand name version of gabapentin) used alone. In one study, patients with newly diagnosed partial seizures were treated with either Neurontin or carbamazepine (Tegretol, Carbatrol) (Beydoun, 1999). In this study, the two medications had a similar effect on the occurrence of seizures, but fewer patients taking Neurontin had to withdraw because of side effects.

Another study looked at patients who had been taking one or two other seizure medicines but continued to experience complex partial seizures or secondarily generalized seizures. These patients were gradually switched to Neurontin used alone at various doses. Each patient had to withdraw if seizures became more frequent. Overall, 20% completed 16 weeks of treatment with Gabapentin alone. This percentage was higher for those who had previously been taking only one medication, but it was lower for those who had been taking carbamazepine (Tegretol, Carbatrol).