Should generic substitution of antiepileptic drugs be restricted?

August 6, 2007

This article tackles whether generic substitution should be banned for antiepileptic drugs. More states have introduced such legislation, raising concerns.

Said Nicholson, all the bills are similar, basically requiring the pharmacist or pharmacy personnel to notify the prescriber or the patient (or the patient's agent), or both, and in some cases getting written consent from one or both, prior to generic substitution. So far, only Tennessee's bill has been signed by the governor, Nicholson said. The Tennessee bill, which went into effect last month, requires notification of both the prescriber and the patient, but is not clear on whether that has to be in writing.

Behind the legislation

Regardless of the source, the spate of legal initiatives has raised concerns and issues within the pharmacy community, ranging from professional to healthcare to business.

Those bills requiring pharmacists to obtain the patient's consent are particularly troubling to Nicholson. "If the pharmacist is asking the patient if he or she is OK with the substitution, it places doubt in the mind of the patient as to the quality of the drug, and it erodes the relevancy of the pharmacist. It takes away the pharmacist's professional judgment in deciding if the generic product is equivalent and appropriate for the patient."

The issue of whether a generic drug is equivalent to a previously prescribed brand-name AED is at the heart of the legislative arguments. Proponents of bills to make substitution more difficult emphasize that AB-rated drugs could have a bioequivalence difference of as much as 20% (80%-120% of the brand product)-too great a range for a complex disease like epilepsy, they caution. "But in the Food & Drug Administration's bioequivalence report issued this year, most of the generic AEDs are in the range of 3.5%," argued Tom Engels, VP of public affairs, Pharmacy Society of Wisconsin.

Concerns with epilepsy

Welty thinks bioequivalence among epileptic drugs is a legitimate concern, but that it's an issue better taken up with a higher authority. Welty said, "The pharmacy community has to address the problem with the FDA. Are the current standards appropriate for a unique disease state like epilepsy?" He cited several concerns with epilepsy where even a slight variance could be problematic: