Sometimes one kind of medicine changes the way another kind of medicine works in the body. If two kinds of medicine affect each other, the doctor may prescribe something else or change the amount to be taken.

How does Felbatol affect other medicines?
Felbatol makes birth control pills less effective, so the chances of becoming pregnant are greater. Women who use pills for birth control should talk to the doctor who prescribed them right away if they start taking Felbatol. The same is true for some other forms of birth control such as Depo-Provera or implants. Felbatol does not affect barrier types of birth control, like condoms, IUDs, and diaphragms.

Felbatol affects the way the body handles many other medicines. If you take Felbatol and another seizure medicine, the dosage of the other medicine may need to be adjusted.

For example, taking Felbatol may increase the level of these seizure medicines in the blood:

• Dilantin or Phenytek (phenytoin)
• carbamazepine-epoxide (the breakdown product of Tegretol, Tegretol XR and Carbatrol)
• phenobarbital
• Depakote and other valproate medicines (Depakene, valproic acid)

How do other medicines affect Felbatol?
Your body gets rid of Felbatol quicker if you are also taking certain seizure medicines, such as:

• Dilantin or Phenytek (phenytoin)
• Tegretol, Tegretol XR, or Carbatrol (carbamazepine)
• phenobarbital