Is It Safe to Take Phenytoin, the Generic Version of Dilantin?

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Brand vs Generic Medication. Tetra Images - Daniel Grill / Getty Images

Safety of Generic Medication

According to the U.S. Food and Drug Administration (FDA), the active ingredient in a generic drug is equivalent to the brand-name version. More than 55% of all the medications prescribed in the United States are generics.

For the most part, generic medications are as safe and effective as the brand-name version of the drug. Several of the major U.S. drug companies manufacture generics, and the world's largest maker of generic drugs, TEVA, is an Israeli company with very high standards.

Generic pills do differ, however, in the inactive ingredients, such as color, flavoring, preservatives and the filler materials that hold the pill or tablet together. Although uncommon, some people may be allergic to one or more of these inactive ingredients.

Issues with Seizure Medications

For some people using certain medications, generics can be a problem. This is most often a problem with medications in which even a minuscule change in dose can be ineffective or cause side effects. Dilantin (phenytoin) is one of those medications.

Some people with epilepsy report problems with generic seizure medications. Doctors who treat people with epilepsy have also reported that some people have “breakthrough” seizures when switching from brand to generic versions of a seizure drug -- or among generics made by different manufacturers. A “breakthrough” seizure is one that occurs unexpectedly in someone who has had good seizure control.

Organizations Provide Guidance

According to the Epilepsy Foundation, the organization has opposed “mandatory substitution of generic drugs for brand names since generics first became available because of concerns about reported breakthrough seizures in some people with epilepsy when they are switched from one version of a medication to another. Other medical organizations focused on the treatment of epilepsy have had similar positions.”

The Epilepsy Foundation notes that many people with epilepsy can safely use generic epilepsy medications to save money, but the decision to do so should be left up to you and your doctor. Your health plan should not mandate the use of generic medications to treat epilepsy.

According to the American Academy of Neurology, "The Food and Drug Administration has allowed for significant differences between name-brand and generic drugs. This variation can be highly problematic for patients with epilepsy. Even minor differences in the composition of generic and name-brand anticonvulsant drugs for the treatment of epilepsy can result in breakthrough seizures."

Dealing with Your Health Plan

If your health plan will not pay for the brand-name version of your epilepsy medication, you and your doctor can appeal. All health plans have appeal mechanisms and often a phone call from your doctor will allow you to get brand-name epilepsy medication, if appropriate.