INNOVATIONS in pharmacy

Ambulatory care pharmacist evaluation of drug-drug interactions with nirmatrelvir/ritonavir: Managing workload and ensuring patient safety during the COVID-19 pandemic

Abigail Pape

South Dakota State University

https://orcid.org/0009-0008-5258-3312

Emily Van Klompenburg

South Dakota State University

https://orcid.org/0000-0003-2376-5228

DOI: https://doi.org/10.24926/iip.v17i1.6934

Keywords: nirmatrelvir/ritonavir, COVID-19, ambulatory care pharmacist, drug-drug interactions, pharmacist workload, patient safety

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Abstract

Background: Nirmatrelvir/ritonavir, an oral antiviral for COVID-19, was released under an Emergency Use Authorization in December 2021. Its complex drug-drug interaction (DDI) profile, combined with limited initial guidance on DDI management, created a critical need for pharmacist-led interventions to ensure safe use.

Objectives: The objective of this study was to evaluate the frequency, type, and interventions for DDIs identified by an ambulatory care pharmacist in a rural clinic during a period when comprehensive guiding literature on nirmatrelvir/ritonavir was unavailable.

Methods: A retrospective electronic medical record review was conducted at a rural South Dakota clinic for patients seen January 1 to September 12, 2022. Adult patients with confirmed COVID-19 who were assessed by the pharmacist for antiviral therapy eligibility were included. Pharmacist-identified DDIs and interventions were categorized by type, and time spent per evaluation was recorded.

Results: Of the 141 included evaluations, 103 (73.0%) had at least one DDI identified, with a total of 195 interactions across 73 drugs. Most common drug classes involved were statins, opioids, and calcium channel blockers. Multiple DDIs were found in 52 evaluations and 32 evaluations required more than one drug intervention. Time spent on evaluations averaged 35 minutes. Despite incomplete guidance, pharmacist assessments aligned with later published data.

Conclusion: In the absence of comprehensive resources, the ambulatory care pharmacist played a critical role in identifying and managing potential DDIs. This study highlights the clinical value and workload burden of pharmacists practicing in settings where DDI evaluation occurs prior to prescribing, such as this clinic-based model. These findings underscore the importance of recognizing and appropriately reimbursing pharmacist contributions within ambulatory care practices.

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Author Biographies

Abigail Pape, South Dakota State University

PharmD Student

Emily Van Klompenburg, South Dakota State University

Assistant Professor of Pharmacy Practice

College of Pharmacy and Allied Health Professions