How well does Keppra XR work?

Keppra XR is generally used as add-on (adjunctive) therapy for partial seizures in adults whose seizures are not well controlled by other medications.

In a number of tests in which immediate release Keppra was compared to a pill with no active medicine (a placebo), Keppra was significantly more effective than the placebo for people with frequent partial seizures. Between 21% and almost 40% of those who took Keppra as add-on therapy reduced their seizure frequency by half or more, without excessive side effects. The rate of side effects was lower than reported for most other seizure medicines.

No single combination of seizure medicines is perfect for everyone. Sometimes, a series of combinations must be tried before finding what is best for the individual. Because Keppra XR doesn't interact with other medicines, dosages don't need to be changed when it is given as add-on therapy for seizures or when medicines are taken for other disorders.

At least one study has found that Keppra also may be effective when used alone to treat partial seizures. Keppra was first given as add-on therapy, and the other seizure medicines were gradually stopped if the person's seizure frequency was reduced by at least half. More than half of these people continued to have at least 50% fewer seizures with Keppra alone.