Evaluating Nirmatrelvir-Ritonavir (Paxlovid®) in Outpatient COVID-19 Treatment: Safety, Tolerability, and Adherence Insights from Primary Healthcare Clinics

Abstract Objective: This study aims to fill this gap by evaluating the safety, tolerability, and adherence of patients prescribed Paxlovid® in outpatient settings, focusing on its use in managing category 2 COVID-19 patients across three primary healthcare clinics in Selangor, Malaysia. Design: Retrospective cross-sectional study Setting: Data were collected from the Paxlovid® pharmacy registry and medical records at Klinik Kesihatan Seksyen 7, Klinik Kesihatan Seksyen 19, and Klinik Kesihatan Kelana Jaya between April 1, 2022, and November 30, 2022. Participants: This study analysed data from 415 category 2 COVID-19 patients aged ≥18 years old. Primary and secondary outcomes: Parameters assessed included patient demographics, dosing, current medication, changes in drug regimen, adherence, and ADR. Pharmacists follow-ups were conducted on days 3 and 5 post-medication initiation. Results: The majority (79.5%) of the cohort experienced ADR, predominantly dysgeusia, diarrhoea, body ache, vomiting, and nausea. Despite these, the ADR were generally well-tolerated, with no severe impacts reported. High adherence was observed, with 96.9% of patients completing the 5-day regimen. The primary reasons for non-adherence included adverse effect intolerability, dosing ambiguity, forgetfulness, concerns about ADR, and perceived health improvement. Notable medications interacting with Paxlovid® were simvastatin, amlodipine, and atorvastatin, and 21.7% of 23 concurrent medications were found not complying to the recommended interventions by the University of Liverpool COVID-19 Drug Interaction database. Conclusion: Nirmatrelvir-ritonavir (Paxlovid®) demonstrates a high level of safety and tolerability in outpatient COVID-19 patients, with optimal adherence observed. This study underscores the vital role of healthcare professionals in managing Paxlovid® within primary healthcare and highlights the need for broader research and direct patient involvement to enhance treatment strategies against COVID-19.