Sometimes one kind of medicine changes the way another kind of medicine works in the body. This is true not only for prescription medicines, but also for medicines you just pick up off the shelf at the store. It's also true for herbal products, vitamins, a few kinds of food, and even cigarettes!

Any time a doctor suggests a new prescription, be sure to talk about what other medicines you are already using. If two kinds of medicine affect each other, the doctor may want to prescribe something else or change the amount to be taken.

Zarontin is less likely than many other seizure medicines to interact with other medications, however. The most important thing to know is that the level of Zarontin in the blood is reduced if it is taken along with certain other seizure medicines. The amount of Zarontin taken may need to be increased if you start taking one of these medicines.

The seizure medicines with this effect are:

• Tegretol, Carbatrol (carbamazepine)
• Dilantin, Phenytek (phenytoin)
• Mysoline (primidone)
• phenobarbital