Risk of pharmacokinetic interactions between antiepileptic and other drugs in older persons and factors associated with risk

• Type of Material: Article
• Authors: Edward Faught Jr, Emory University; Jerzy P. Szaflarski, University of Alabama Birmingham; Joshua Richman, University of Alabama Birmingham; Ellen Funkhouser, University of Alabama Birmingham; Roy C. Martin, University of Alabama Birmingham; Kendra Piper, Emory University; Chen Dai, University of Alabama Birmingham; Lucia Juarez, University of Alabama Birmingham; Maria Pisu, University of Alabama Birmingham
• Language: English
• Date: 2018-03-01
• Publisher: Wiley: 12 months
• Publication Version: Author Accepted Manuscript (After Peer Review)
• Copyright Statement: Wiley Periodicals, Inc. © 2018 International League Against Epilepsy
• Final Published Version (URL): http://dx.doi.org/10.1111/epi.14010
• Title of Journal or Parent Work: Epilepsia
• ISSN: 0013-9580
• Volume: 59
• Issue: 3
• Start Page: 715
• End Page: 723
• Grant/Funding Information: This study was funded by the National Institute of Neurological Disorders and Stroke (1RO1NS080898–01, Maria Pisu, Principal Investigator)
• Keywords: QUALITY; MEDICARE BENEFICIARIES; CARE; seizures; interactions; race; epilepsy; US; Neurosciences & Neurology; SEIZURES; VETERANS; Clinical Neurology; antiepileptic drugs; ADULTS; Science & Technology; ethnicity; NEW-ONSET EPILEPSY; CHOICE; Life Sciences & Biomedicine; CLINICAL COMORBIDITY INDEX
• Research Categories: Health Sciences, Pharmacology; Biology, Neuroscience

Abstract

Objective: To determine the frequency of older Americans with epilepsy receiving concomitant prescriptions for antiepileptic drugs (AEDs) and non-epilepsy drugs (NEDs) which could result in significant pharmacokinetic (PK) interaction, and to assess the contributions of racial/ethnic, socioeconomic, and demographic factors. Methods: Retrospective analyses of 2008-2010 Medicare claims for a 5% random sample of beneficiaries ≥67 years old in 2009 augmented for minority representation. Prevalent cases had ≥1 ICD-9 345.x or ≥2 ICD-9 780.3x, and ≥1 AED. Among them, incident cases had no seizure/epilepsy claim codes nor AEDs in preceding 365 days. Drug claims for AEDs, and for the 50 most common NEDs within +/− 60 days of the index epilepsy date were tabulated. Interacting pairs of AEDs/NEDs were identified by literature review. Logistic regression models were used to examine factors affecting the likelihood of interaction risk. Results: Interacting drug pairs affecting NED efficacy were found in 24.5% of incident, 39% of prevalent cases. Combinations affecting AED efficacy were found in 20.4% of incident, 29.3% of prevalent cases. Factors predicting higher interaction risk included having ≥ 1 comorbidity, being eligible for Part D low Income Subsidy, and not living in the northeastern US. Protective factors were Asian race/ethnicity, and treatment by a neurologist. Significance: A substantial portion of older epilepsy patients received NED-AED combinations that could cause important PK interactions. The lower frequency among incident vs. prevalent cases may reflect changes in prescribing practices. Avoidance of interacting AEDs is feasible for most persons because of the availability of newer drugs.