WASHINGTON, DC—A majority of pharmacists have concerns about filling a prescription with a generic antiepileptic drug (AED) if the patient has been taking a branded AED, according to research presented at the 67th Annual Meeting of the American Epilepsy Society. But for most other classes of medications, pharmacists are not concerned about switching patients from a branded drug to a generic one.
“It [is] interesting that they’re more concerned about the brand–generic switches than they are [about] generic–generic switches,” said Lisa Garrity, Pharm D. “Those [switches] should be equally concerning.”
After generic versions of several new AEDs became available, some patients and physicians reported that the generic medications were not working as well as the branded products had. Patients reported that certain generic drugs did not control seizures well and that others produced side effects.
Dr. Garrity, Clinical Pharmacy Specialist in Neurology at Cincinnati Children’s Hospital, and colleagues developed a survey to examine retail pharmacists’ knowledge about switches from branded to generic medications, and to learn how pharmacists are addressing drug variability with patients and their physicians. The group sent the survey to 30 retail pharmacists in the Cincinnati area.
The findings indicate that patients are telling pharmacists about their concerns regarding changes in the manufacturer of their AEDs. About 30% of the pharmacists surveyed knew of patients who had had breakthrough seizures or adverse effects associated with a change in manufacturer. “It’s anecdotal information, but it’s still striking that it’s that well known in the pharmacy community,” said Dr. Garrity. On the other hand, retail pharmacists were unable to correctly identify the bioequivalence range (ie, between 80% and 125%) that the FDA uses to approve generic drugs.
“The encouraging thing is that pharmacists are willing to let patients know that these manufacturer changes are occurring and to try to keep the same manufacturer in stock if possible,” she added. “One area that needs work is the communication with prescribers about when these manufacturer changes occur.”
Trial Examines Branded and Generic Lamotrigine
Michael Privitera, MD, Professor of Neurology at the University of Cincinnati Neuroscience Institute, is investigating potential differences between branded and generic AEDs in two prospective, randomized trials. In one study, participants with epilepsy who are taking several AEDs will receive a single dose of branded lamotrigine, a single dose of one generic version of lamotrigine two weeks later, and a second generic version of lamotrigine two weeks after that. The other trial is a chronic-dose study of people with epilepsy already receiving lamotrigine who will receive two different generic formulations of the drug. “We chose the drug lamotrigine first because there were a number of complaints about lamotrigine,” Dr. Privitera explained.
In addition, both studies are examining whether changing a patient from a generic drug at the low end of the bioequivalence range to a generic drug at the high end of the bioequivalence range is associated with any blood level or clinical difference. Results of the two trials will be available later this year.
Separate investigations are measuring the actual amount of active ingredient in 25- and 100-mg tablets of branded and generic lamotrigine, said Dr. Privitera. The group also is examining content uniformity, or the degree of variation in drug content between pills in the same manufacturing lot. The investigators used the results from these laboratory studies to choose the generic products that were most different to use in the comparison studies previously described.
“The concern about generics has been driven by perceptions, anecdotal reporting, [and] retrospective analyses,” said Barry Gidal, Pharm D, Professor of Pharmacy and Neurology at the University of Wisconsin–Madison School of Pharmacy, who is collaborating with Dr. Privitera. The trials are intended to provide evidence and to determine what guidance can be provided to the FDA about the variability of, and the proper way to evaluate, generic and branded AEDs, he added.
Manufacturing Variability May Not Affect Most Patients
Current regulations do not require the manufacturer of a generic drug to publish its data on the drug. If available, the data could help clinicians, pharmacists, and nurses make informed decisions about generic drugs’ performance. “This should be transparent,” said Dr. Gidal. “Right now, it’s not transparent at all.”
Patients need to advocate for themselves, Dr. Gidal continued. They should ask their pharmacists who manufactured their generic AED and what the lot number is. This information may be helpful in the event of a problem. Each patient also should build a relationship with one pharmacist, Dr. Gidal added.
Patients who have problems with a generic AED should tell their pharmacist, their physician, and the FDA, said Dr. Garrity. “There are mechanisms to report potential adverse effects. That’s something that’s really underutilized, and that’s a way that patients can be empowered. Anyone can report these things. The more information we know about these concerns, the more we can address them.”