Prevalence and management of drug–drug interaction of nirmatrelvir/ritonavir in patients with COVID-19: A real-life practice in Thailand

Pharmacy Practice

  • Pongsakorn Charoenviwattanakij1College of Pharmacotherapy of Thailand, Nonthaburi, Thailand.
  • Wichai Santimaleeworagun2Department of Pharmacy, Faculty of Pharmacy, Silpakorn University, Nakhon Pathom, Thailand.
  • Watsa Charoenwaiyachet3Department of Pharmacy, King Chulalongkorn Memorial Hospital, Thai Red Cross Society, Bangkok, Thailand.
  • Chotirat Nakaranurack4Department of Pharmacy Practice, Faculty of Pharmaceutical Sciences, Chulalongkorn University, Bangkok, Thailand.

Volume 23 Issue 4 Pages 1-13

DOI: 10.18549/PharmPract.2025.4.3271

Abstract

Background: Nirmatrelvir/ritonavir is a novel oral antiviral medication for coronavirus disease 2019 (COVID-19). Most international guidelines recommend nirmatrelvir/ritonavir for treating patients with mild to moderate COVID-19 who are at high risk of progressing to severe COVID-19. However, concerns have appeared regarding potential drug–drug interactions (DDIs) caused by CYP3A4 inhibition with ritonavir. Objective: This study aims to investigate the prevalence of potential drug interactions in outpatients with COVID-19 who received nirmatrelvir/ritonavir. Additionally, we evaluated the management of drug-drug interactions, 30-day hospitalization, 30-day mortality, and adverse drug events related to nirmatrelvir/ritonavir. Methods: This retrospective study, conducted at King Chulalongkorn Memorial Hospital in Thailand, included patients who received nirmatrelvir/ritonavir for COVID-19 treatment in the outpatient department from May to August 2022. Pharmacists encouraged physicians to check for potential drug-drug interactions (DDIs) with the patient's other medications before prescribing nirmatrelvir/ritonavir. Additionally, pharmacist followed up with the patients after they received nirmatrelvir/ritonavir. The DDIs were categorized as "potentially clinically significant interactions" or "should not be co-administered" based on the Liverpool Drug assessments. Results: Of the 221 prescriptions analyzed, 138 (62.4%) had at least one pair of DDIs, causing a total of 184 interactions determined with nirmatrelvir/ritonavir. The most prevalently involved drugs in interactions with nirmatrelvir/ritonavir were simvastatin (32.6%), atorvastatin (28.3%), and manidipine (17.4%). Of the prescriptions, 106 (57.6%) were intervened by physicians following the protocol or recommendation from the database, with statins being the most intervened group. Calcium channel blockers, such as manidipine and lercanidipine, were the most common group observed for drug interactions. The observed group involved three patients suspected of adverse drug events. A total of 13 (5.9%) patients were hospitalized but not drug interactions-related. The most predominant adverse drug reaction for nirmatrelvir/ritonavir was dysgeusia (51.1%). Conclusion: Our study emphasizes the importance of evaluating and managing potential DDIs associated with nirmatrelvir/ritonavir in COVID-19 patients. Implementing protocols to check for interactions before prescription is crucial along with developing comprehensive monitoring strategies.

Keywords

  • prevalence
  • drug interactions
  • nirmatrelvir/ritonavir
  • COVID-19
Pharmacy Practice

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