Abstract: Objective To investigate the safety of nirmatrelvir/ritonavir in the treatment of novel coronavirus infections (COVID-19), and to provide reference for clinical use. Methods The medical records of adult patients infected with COVID-19 who were admitted to the Affiliated Hospital of Guangdong Medical University between December 15, 2022 and February 15, 2023 and treated with Paxlovid were retrospectively investigated via the electronic medical record system. The data on adverse reactions related to paxlovid, including the time of occurrence, clinical manifestations, severity, management and outcomes was analyzed before the clinical characteristics of patients with and without adverse reactions were compared. Results A total of 326 patients were enrolled, including 225 males (69.02%) and 101 females (30.98%). Fifty-six adverse drug reactions occurred in 55 patients, so the incidence was 16.87%, including 28 cases of digestive system injury, 17 cases of liver dysfunction, 4 cases of nervous system injury, 3 cases of respiratory system injury, and 3 other cases. Among them, one patient experienced both respiratory and digestive system injury. There were 18 cases (32.73%) of grade 1, 37 cases (67.27%) of grade 2, and no serious (grade ≥3) adverse drug reactions according to the grading of severity. The clinical outcomes were generally good after drug withdrawal/reduction and symptomatic treatment. Twenty-eight of these cases (50.91%) were cured, 24 cases (43.64%) improved, and 3 cases (5.45%) were out of contact. There was no statistically significant difference in the clinical characteristics (gender, age, and various comorbidities) between patients with and without adverse reactions (P>0.05). Conclusion Paxlovid is safe in the treatment of COVID-19, with mild symptoms of adverse reactions manifested as diarrhea and liver function abnormalities, and is well tolerated by patients.

Key words: novel coronavirus infection, nirmatrelvir, ritonavir, nirmatrelvir/ritonavir, antiviral drug, adverse drug reactions, safety