The Pros and Cons of Transdermal Anti-epileptic Drugs

If well-tested, there are many pros to using transdermal drugs to treat epilepsy in cats, explains Heidi Barnes Heller, DVM, DACVIM (Neurology), clinical associate professor of neurology/neurosurgery at the University of Wisconsin-Madison School of Veterinary Medicine.

"The pros to transdermal is most certainly the ease-of-use. Transdermal drugs are very easy to use in that, if you apply them properly, they can be absorbed if they've been well-tested in a fashion that makes them easily used by both the applicator—the owner or caregiver—as well as the cat.

The downsides are that they really need to be well tested before they're put out into general use because there's a general sense of if I put it into a transdermal and give it to an animal it will be the same as oral. And that is absolutely not the truth. We have found very big differences in transdermal phenobarbital compared to oral phenobarbital in how it is interacted in the body, how it is distributed, how well it is absorbed on an individual cat basis. And so it's very important that people who use transdermal use a product that has been tested to be shown to be useful as a transdermal drug. In other words, not that it just is convenient, but that it also is well absorbed, we know the absorptive pattern of it, we know how it's being manufactured, we know what the carrier molecule is, we know what the shelf life is for that product once it's made up, we know if it should be refrigerated, we know if it should stay in room air.

There's so many factors that go into making an appropriate transdermal that I think that cons are that it's perhaps used more casually and probably shouldn't be."