2015/04/14 by Juan Tamargo, Jean-Yves Le Heuzey, Jean‐Yves Le Heuzey +1 · 2 citations
Mathematics · Medicine · #Cardiac electrophysiology and arrhythmias #Pharmaceutical studies and practices #Statistical Methods in Clinical Trials
paper · pdf · doi:10.1007/s00228-015-1832-0
openalex publication_date 2015/04/14 · crossref created 2015/04/14 · crossref issued 2015/04/15 · crossref published 2015/04/15 · crossref published-online 2015/04/15 · crossref published-print 2015/05/01 · crossref deposited 2024/06/08 · openalex created_date 2025/10/10 · crossref indexed 2026/07/31 · openalex updated_date 2026/08/01
PURPOSE: The therapeutic index (TI) is the range of doses at which a medication is effective without unacceptable adverse events. Drugs with a narrow TI (NTIDs) have a narrow window between their effective doses and those at which they produce adverse toxic effects. Generic drugs may be substituted for brand-name drugs provided that they meet the recommended bioequivalence (BE) limits. However, an appropriate range of BE for NTIDs is essential to define due to the potential for ineffectiveness or adverse events. Flecainide is an antiarrhythmic agent that has the potential to be considered an NTID. This review aims to evaluate the literature surrounding guidelines on generic substitution for NTIDs and to evaluate the evidence for flecainide to be considered an NTID. METHODS: A review of recommendations from various regulatory authorities regarding BE and NTIDs, and publications regarding the NTID characteristics of flecainide, was carried out. RESULTS: Regulatory authorities generally recommend reduced BE limits for NTIDs. Some, but not all, regulatory authorities specify flecainide as an NTID. The literature review demonstrated that flecainide displays NTID characteristics including a steep drug dose-response relationship for safety and efficacy, a need for therapeutic drug monitoring of pharmacokinetic (PK) or pharmacodynamics measures and intra-subject variability in its PK properties. CONCLUSIONS: There is much evidence for flecainide to be considered an NTID based on both preclinical and clinical data. A clear understanding of the potential of proarrhythmic effects or lack of efficacy, careful patient selection and regular monitoring are essential for the safe and rational administration of flecainide.