The February 2013 issue of Treatment Guidelines from The Medical Letter is on Drugs for Epilepsy, a field that in some ways is different from anything else in therapeutics. For one thing, placebo-controlled trials of antiepileptic drugs would be unethical. If you have seizures, you won’t want to volunteer to participate in a study that could randomize you to a placebo. So in the absence of the sorts of trials that form the basis of approval for most new drugs, the FDA approves new drugs for epilepsy only for patients with seizures that have not responded to anything else, and then lets them gradually work their way into everyday usage for the more common, easier-to-treat seizures.
Another odd thing about drugs for epilepsy is that they are all about equally effective. Well, not for every type of seizure, but among those that are used for a given type of seizure, there doesn’t seem to be any great difference between them in how well they prevent it. In most fields of therapeutics, that’s what all the fighting (advertising) is about: my drug works much better than yours. But in epilepsy, not so much.
Another oddity is that neurologists who specialize in taking care of patients with epilepsy will go to great lengths (high doses) in the use of one drug before prescribing a second one. In other disorders like diabetes, hypertension or glaucoma, clinicians often add on a second drug when the first one hasn’t done the job it was supposed to do. The drugs used to treat epilepsy often interact with each other in ways that make them difficult to manage, so practitioners tend to raise the dosage of one drug to the point of toxicity before going on to a second agent, and if they have to use a second drug, they usually stop the first one rather than adding on.
Click here to listen to a conversation with our Contributing Editor, Carl Bazil, MD, Director, Division of Comprehensive Epilepsy Center and Sleep Center at Columbia University.