Skip to main content
Advertisement

Main menu

  • Home
  • Articles
    • Current Issue
    • Fast Forward
    • Latest Articles
    • Special Sections
    • Archive
  • Information
    • Instructions to Authors
    • Submit a Manuscript
    • FAQs
    • For Subscribers
    • Terms & Conditions of Use
    • Permissions
  • Editorial Board
  • Alerts
    • Alerts
    • RSS Feeds
  • Virtual Issues
  • Feedback
  • Submit
  • Other Publications
    • Drug Metabolism and Disposition
    • Journal of Pharmacology and Experimental Therapeutics
    • Molecular Pharmacology
    • Pharmacological Reviews
    • Pharmacology Research & Perspectives
    • ASPET

User menu

  • My alerts
  • Log in
  • My Cart

Search

  • Advanced search
Journal of Pharmacology and Experimental Therapeutics
  • Other Publications
    • Drug Metabolism and Disposition
    • Journal of Pharmacology and Experimental Therapeutics
    • Molecular Pharmacology
    • Pharmacological Reviews
    • Pharmacology Research & Perspectives
    • ASPET
  • My alerts
  • Log in
  • My Cart
Journal of Pharmacology and Experimental Therapeutics

Advanced Search

  • Home
  • Articles
    • Current Issue
    • Fast Forward
    • Latest Articles
    • Special Sections
    • Archive
  • Information
    • Instructions to Authors
    • Submit a Manuscript
    • FAQs
    • For Subscribers
    • Terms & Conditions of Use
    • Permissions
  • Editorial Board
  • Alerts
    • Alerts
    • RSS Feeds
  • Virtual Issues
  • Feedback
  • Submit
  • Visit jpet on Facebook
  • Follow jpet on Twitter
  • Follow jpet on LinkedIn
Review ArticleMinireview

Therapeutic Basis of Generic Substitution of Antiseizure Medications

Sarah Elmer and Doodipala Samba Reddy
Journal of Pharmacology and Experimental Therapeutics May 2022, 381 (2) 188-196; DOI: https://doi.org/10.1124/jpet.121.000994
Sarah Elmer
Department of Neuroscience and Experimental Therapeutics, Texas A&M University Health Science Center College of Medicine, Bryan, Texas
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
Doodipala Samba Reddy
Department of Neuroscience and Experimental Therapeutics, Texas A&M University Health Science Center College of Medicine, Bryan, Texas
  • Find this author on Google Scholar
  • Find this author on PubMed
  • Search for this author on this site
  • Article
  • Figures & Data
  • Info & Metrics
  • eLetters
  • PDF
Loading

Abstract

More than thirty antiseizure medications (ASMs) are available for treating epilepsy. ASMs differ in their potency and efficacy in controlling seizures by acting on diverse targets in the brain, often with variable pharmacokinetics. Moreover, nearly 30% of people with epilepsy have drug-resistant or intractable seizures. Generic substitution of ASMs is a complex issue. It is thought that frequent generic substitution in people with epilepsy may cause problems because the U.S. Food and Drug Administration (FDA) rules allow too much variability across products. The standard bioequivalence range (80% to 125%) appears too broad for many ASMs, especially those exhibiting little separation between therapeutic and toxic levels. Hence, sub-therapeutic concentration may lead to therapeutic failure with seizure recurrence, which could be life threatening. A supra-therapeutic level could result in adverse effects or compliance issues. There are reported issues with generic substitutions of phenytoin, topiramate, levetiracetam, carbamazepine, and lamotrigine. There is discussion in the epilepsy community about additional guidelines, including designation of generic ASMs as Narrow Therapeutic Index (NTI) drugs and how patient education plays a role in generic substitution. Overall, based on the published evidence on specific generic ASMs, FDA bioequivalence standards are not the cause of problems with generic ASM substitution. Rather, it is imperative that physicians and pharmacists provide adequate patient education on what to expect when switching to generic ASMs, including changes in medication shape and color. Another suggestion would be to consider that all ASMs be considered for inclusion in NTI class to prevent the clinical outcome issues associated with generic ASM switching.

SIGNIFICANCE STATEMENT There are critical aspects to consider when switching from a brand name antiseizure medication (ASM) when a generic becomes available or switching between generics. Generic ASMs are interchanged with little consideration of differences in therapeutic equivalence and other clinical factors. This article describes key issues on generic substitution of ASMs and highlights critical pharmacotherapeutic issues associated with generic ASMs.

Footnotes

    • Received October 27, 2021.
    • Accepted February 25, 2022.
  • This work was supported by National Institutes of Health National Institute of Neurological Disorders and Stroke [Grants R21-NS052158 and R01-NS051398 to DSR]; CounterACT Program, National Institutes of Health, Office of the Director and the National Institute of Neurologic Disorders and Stroke [Grant R21-NS076426, U01-NS083460, R21-NS099009, U01-NS117209, U01-NS117278 to DSR]; and Texas A&M Presidential X-Grant (to DSR). Sarah Elmer received a summer research stipend from the Texas A&M University College of Medicine.

  • No author has an actual or perceived conflict of interest with the contents of this article.

  • https://doi.org/10.1124/jpet.121.000994.

  • Copyright © 2022 by The American Society for Pharmacology and Experimental Therapeutics
View Full Text

JPET articles become freely available 12 months after publication, and remain freely available for 5 years. 

Non-open access articles that fall outside this five year window are available only to institutional subscribers and current ASPET members, or through the article purchase feature at the bottom of the page. 

 

  • Click here for information on institutional subscriptions.
  • Click here for information on individual ASPET membership.

 

Log in using your username and password

Forgot your user name or password?

Purchase access

You may purchase access to this article. This will require you to create an account if you don't already have one.
PreviousNext
Back to top

In this issue

Journal of Pharmacology and Experimental Therapeutics: 381 (2)
Journal of Pharmacology and Experimental Therapeutics
Vol. 381, Issue 2
1 May 2022
  • Table of Contents
  • Table of Contents (PDF)
  • About the Cover
  • Index by author
  • Editorial Board (PDF)
  • Front Matter (PDF)
Download PDF
Article Alerts
Sign In to Email Alerts with your Email Address
Email Article

Thank you for sharing this Journal of Pharmacology and Experimental Therapeutics article.

NOTE: We request your email address only to inform the recipient that it was you who recommended this article, and that it is not junk mail. We do not retain these email addresses.

Enter multiple addresses on separate lines or separate them with commas.
Therapeutic Basis of Generic Substitution of Antiseizure Medications
(Your Name) has forwarded a page to you from Journal of Pharmacology and Experimental Therapeutics
(Your Name) thought you would be interested in this article in Journal of Pharmacology and Experimental Therapeutics.
CAPTCHA
This question is for testing whether or not you are a human visitor and to prevent automated spam submissions.
Citation Tools
Review ArticleMinireview

Generic Substitution of Antiseizure Medications

Sarah Elmer and Doodipala Samba Reddy
Journal of Pharmacology and Experimental Therapeutics May 1, 2022, 381 (2) 188-196; DOI: https://doi.org/10.1124/jpet.121.000994

Citation Manager Formats

  • BibTeX
  • Bookends
  • EasyBib
  • EndNote (tagged)
  • EndNote 8 (xml)
  • Medlars
  • Mendeley
  • Papers
  • RefWorks Tagged
  • Ref Manager
  • RIS
  • Zotero

Share
Review ArticleMinireview

Generic Substitution of Antiseizure Medications

Sarah Elmer and Doodipala Samba Reddy
Journal of Pharmacology and Experimental Therapeutics May 1, 2022, 381 (2) 188-196; DOI: https://doi.org/10.1124/jpet.121.000994
del.icio.us logo Digg logo Reddit logo Twitter logo Facebook logo Google logo Mendeley logo
  • Tweet Widget
  • Facebook Like
  • Google Plus One

Jump to section

  • Article
    • Abstract
    • Introduction
    • Substitution of Generic ASMs
    • Generic Drug Approval Process
    • Reported Bioequivalence and Therapeutic Problems with Generic ASMs
    • Clinical Considerations for Changing Between Generic ASMs
    • Studies Investigating Generic Substitution of ASMs
    • Conclusions and Perspectives
    • Authorship Contributions
    • Footnotes
    • Abbreviations
    • References
  • Figures & Data
  • Info & Metrics
  • eLetters
  • PDF

Related Articles

Cited By...

More in this TOC Section

  • Potential Therapeutic Approaches to Nociplastic Pain
  • Attenuation of Drug Response with Repeated Doses
Show more Minireview

Similar Articles

Advertisement
  • Home
  • Alerts
Facebook   Twitter   LinkedIn   RSS

Navigate

  • Current Issue
  • Fast Forward by date
  • Fast Forward by section
  • Latest Articles
  • Archive
  • Search for Articles
  • Feedback
  • ASPET

More Information

  • About JPET
  • Editorial Board
  • Instructions to Authors
  • Submit a Manuscript
  • Customized Alerts
  • RSS Feeds
  • Subscriptions
  • Permissions
  • Terms & Conditions of Use

ASPET's Other Journals

  • Drug Metabolism and Disposition
  • Molecular Pharmacology
  • Pharmacological Reviews
  • Pharmacology Research & Perspectives
ISSN 1521-0103 (Online)

Copyright © 2022 by the American Society for Pharmacology and Experimental Therapeutics