Are Generic Antiepileptics the Same as the Brand Name?

Should You Make the Switch?

Pills spilling out of a bottle and forming a prescription sign (Rx). Credit: GIPhotoStock / Getty Images

There's been a lot of controversy over whether generic and brand name anti-epileptic medications are what is called "therapeutically equivalent." In other words, there's some question whether or not generic medications work as well as the often much more expensive brand name counterparts. If you're thinking of switching from a brand name drug to a generic anticonvulsant medication, or even if you're considering switching from one generic medication to another, you need to be well versed on this issue in order to make an informed decision.

Of course, you'll also want to be sure and discuss this decision with your physician.

How Generic Medications Come Into Play

When a pharmaceutical company develops a new drug, they often pour millions of dollars into research. This costly process helps to ensure that the medication meets acceptable standards for both safety and effectiveness. The drug company can then justify charging a lot of money for the new brand name medication. About 20 years after the initial patent is filed, the pharmaceutical company loses the right to sole distribution of that medication. In other words, other companies can offer a generic version of the medication at a lower price.

The United States Food and Drug Administration tests all generic formulations of antiepileptics to ensure the medications are interchangeable with brand products. Despite this, physician surveys and case reports suggest that there have been significant problems when switching from brand-name antiepileptic medication to generics.

If the FDA is being so rigorous in testing, how can it be that so many physicians and patients are expressing concerns?

What is the Concern in Switching from a Brand-Name Medication to a Generic?

The FDA deems a generic drug to be "therapeutically equivalent" to a brand-name drug if it has the same amount of the active ingredient, and meets standards for strength, quality, purity, and identity.

Two features are particularly examined:

  • the area-under-the-curve (AUC)
  • the maximum plasma concentration (Cmax).

These features measure how much medication gets absorbed into the bloodstream. The FDA requires that the AUC and Cmax of a generic substitute medication be within 80 percent to 125 percent of the brand-name measures with 90 percent confidence. That seems like a pretty wide margin, especially if the drug in question has a small "therapeutic window" -- the difference between a medication dose that's effective and a medication dose that causes unacceptable side effects.

In addition, tests to establish that generic drugs meet this standard are usually done on about 35 people. This is a very different standard than the often hundreds of people tested for a brand-name drug.

What Does the FDA State About Switching to Generic Medications?

The FDA has stated that there is no solid evidence that there are increased risks of switching to generics. Some supporters of this position suggest that the nocebo effect could play a role in the problems reported by patients after switching.

Whereas the placebo effect involves patients' symptoms improving after receiving an inactive substance (like a sugar pill) because the patient believes the substance will help them, a nocebo effect involves patients' symptoms getting worse because they think an active medication will not help. It's all very hard to say -- perhaps the stress and anxiety associated with switching to a generic triggers a seizure in some people with epilepsy.

A Closer Look at Generic Anti-Epileptics

However, if the lack of effectiveness is simply related to the stress of switching medications, it's unusual that similar effects aren't seen in other kinds of drugs like pain medications. Why should this be more of a problem in patients taking medication for epilepsy? It may simply be that anti-epileptics require very close titration of dose, and that the parameters established by the FDA do not work as well for medications with narrower therapeutic windows.

In this case, the problem is less one of switching from brand name to generic medication, but may also exist when switching from one generic to another, as those doses will also possibly differ. For example, if one generic medication has 125 percent the effective dose found in a brand name anti-epileptic, and you switch to a medication that has 80 percent that dose, your true medication dose has fallen considerably.

What are the Potential Risks of Switching to Generic Medications?

The risks of switching from brand name to generic or between generics will partially depend on which medications are being taken. Patients using Keppra (levetiracetam), Lamictal (lamotrigine) or divalproex are most likely to switch back from generic to brand name products, often for increased seizures or a change in adverse medication reactions. Extra caution is also called when a seizure could be especially dangerous, such as with people who drive, are pregnant, or who have suffered severe consequences of their seizures in the past.

Bottom Line

The reported problems with switching from brand name antiepileptic medication does not mean that all generic anti-epileptic medication should be avoided. Like any other medication, there are likely risks and benefits to switching to generics. These risks and benefits need to be well understood before making a decision to switch. Money will be saved, but there may be some complications of which you need to be aware, or dose adjustments that will need to be made. It's important to recognize the potential for complications even when switching between generic medications, and discuss all of your choices and concerns with your doctor.


American Epilepsy Society (AES) 65th Annual Meeting: FDA town hall meeting. Presented December 2, 2011.

Gidal, B.E. (2012). Generic antiepileptic drugs: How good is close enough? Epilepsy Currents, 12(1):32-34.

Henney, J.E..(1999).  From the food and drug administration. JAMA, 282 1995.

Kramer, G., Steinhoff, B.J., Feucht, M., Pfafflin, M., & May, T.W. (2007). Experience with generic drugs in epilepsy patients: an electronic survey of members of the German, Austrian and Swiss branches of the ILAE. Epilepsia,48(3) :609-611

Krauss, G.J., Caffo, B., Chang, Y.-T., Hendrix, C. W., &Chuang, K. (2011). Assessing bioequivalence of generic antiepilepsy drugs. Annals of Neurology, 70: 221-228. doi: 10.1002/ana.22452

DISCLAIMER: The information in this site is for educational purposes only. It should not be used as a substitute for personal care by a licensed physician. Please see your doctor for diagnosis and treatment of any concerning symptoms or medical condition.

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