A descriptive analysis of drug related problems identified when prescribing the COVID-19 antiviral drug Paxlovid®

Background Paxlovid® is the only licensed oral COVID − 19 antiviral containing nirmatrelvir and ritonavir. Ritonavir is a potent inhibitor of cytochrome P450 enzymes resulting in clinically significant drug-drug interactions (DDIs). Aim To describe the frequency, type, and severity of detected drug related problems (DRPs) with Paxlovid® Method This study involved a retrospective, quantitative data analysis. All patients prescribed Paxlovid® in a public hospital in Vienna, were included. Data was collected from the patients’ records and recorded on a customised and piloted data collection form. Any DRPs were also noted. The severity of DDIs was classified using an established checker tool. Results 122 of 140 (87.1%) patients required interventions to prevent DRPs; 63.6% of cases required intervention by the pharmacist at dispensing. The most common DRPs were DDIs (57.1%). In 24.3% of cases both renal impairment and DDIs were noted. 313 DDIs were recorded in 114 patients; in 24 patients, the interactions recorded were severe. In 3 patients (2.1%), Paxlovid® was prescribed despite being contraindicated due to severe renal impairment requiring pharmacist intervention. Conclusion This study demonstrated that numerous DRPs involving Paxlovid® were identified by the pharmacist following prescribing. Pharmacists’ involvement in prescribing highly interacting drugs such as Paxlovid® is beneficial to enhance patient safety.