Prevalence of potentially inappropriate use of antiviral therapy with simnotrelvir-ritonavir versus nirmatrelvir-ritonavir in hospitalised patients: a retrospective study in Beijing, China.

BACKGROUND: While simnotrelvir-ritonavir and nirmatrelvir-ritonavir, the oral antiviral agents targeting the 3C-like proteases, are widely used in China, robust data on their appropriate use remain limited in hospitalised patients. We therefore examined the appropriateness of simnotrelvir-ritonavir versus nirmatrelvir-ritonavir in the inpatient setting. METHODS: A retrospective study was conducted to compare the potentially inappropriate use of simnotrelvir-ritonavir and nirmatrelvir-ritonavir in hospitalised patients between 1 July 2023 and 31 December 2023 in Beijing, China. Four factors are taken into consideration when defining and critiquing potentially inappropriate use: indications, dosage and timing of administration, contraindications and drug-drug interactions. RESULTS: We have identified 278 simnotrelvir-ritonavir and nirmatrelvir-ritonavir prescriptions in 226 hospitalised COVID-19 patients, of which 49.6% (138 prescriptions) satisfied all the criteria for appropriate use. Nirmatrelvir-ritonavir prescriptions were more likely to have potentially inappropriate indications (12.4% vs 3.2%, p=0.006) or dosage and timing of administration (13.1% vs 4.0%, p=0.009) than simnotrelvir-ritonavir prescriptions. Nirmatrelvir-ritonavir was prescribed to two patients in the presence of contraindications (severe renal impairment). No significant differences were identified in drug-drug interactions (DDIs) (p=0.657) and contraindicated DDIs (p=0.670) between simnotrelvir-ritonavir and nirmatrelvir-ritonavir. The most common contraindicated co-medication was estazolam, followed by quetiapine and clopidogrel. CONCLUSIONS: About half of the patients use simnotrelvir-ritonavir and nirmatrelvir-ritonavir that might potentially be inappropriate. More extensive research is required to supplement the empirical evidence supporting COVID-19 therapeutics. Additionally, appropriate therapy requires collaboration with pharmacists and education on the appropriate use of COVID-19 therapeutics among physicians and patients.