Nirmatrelvir-ritonavir treatment of COVID-19 in a high-risk patient population: A retrospective observational study

Background Coronavirus disease 2019 (COVID-19) is a highly contagious, airborne viral infection that can infect anyone. Those with certain underlying conditions may be at higher risk for infection to develop into a severe disease requiring hospitalization. This report summarizes use of nirmatrelvir-ritonavir for the treatment of COVID-19 in high-risk patients at a single academic medical center through a pharmacist delegation protocol and demonstrates real-world efficacy and safety of treatment. Methods This retrospective, single-center, observational study analyzed all patients who received nirmatrelvir-ritonavir ordered by a clinical pharmacist for treatment of COVID-19 infection. The primary outcomes were safety and efficacy of nirmatrelvir-ritonavir. Safety was evaluated by analyzing drug interaction management and adverse events. Efficacy was evaluated through hospitalization and death within 28 days of nirmatrelvir-ritonavir use. Results Sixty patients were eligible for inclusion. No patients were hospitalized or died within 28 days after initiation of nirmatrelvir-ritonavir. Pharmacists identified 101 drug interactions with 60% considered clinically significant, requiring modification of home medications. Adverse outcomes associated with the use of nirmatrelvir-ritonavir were reported in 13 patients (21.7%). Conclusions A comprehensive program to mitigate drug interactions and prescribe nirmatrelvir-ritonavir ensured timely access to COVID-19 therapy, which may be associated with the prevention of hospitalization and death.