Paxlovid® in Renal Impairment

The Paxlovid^® product information has recently been updated; it is no longer contraindicated in severe renal impairment.

Paxlovid^® is an oral antiviral therapy for COVID-19 that contains nirmatrelvir co-packaged with ritonavir. Nirmatrelvir is a SARS-CoV-2 protease inhibitor that prevents viral replication, while ritonavir inhibits its hepatic metabolism. Co-administration is required to ensure plasma levels of nirmatrelvir reach the target therapeutic range.

When administered with ritonavir, renal excretion becomes the primary route of elimination for nirmatrelvir. Systemic exposure increases as renal function declines. A small open label study evaluated the safety of nirmatrelvir and ritonavir in patients with severe renal impairment. Findings suggest similar safety and efficacy to that observed in placebo-controlled trials that excluded patients with moderate to severe renal impairment.

No dose adjustment is required in mild renal impairment. However, dose reduction is recommended for patients with moderate and severe renal impairment, as outlined in Table 1.

Table 1. Recommended dose adjustments in renal impairment

Abbrev: eGFR, estimated glomerular filtration ratePatients with severe renal impairment are at increased risk of severe COVID-19 outcomes, including hospitalisation and death. Therefore, access to appropriately dose-adjusted antiviral therapy is important. Patients receiving dose-adjusted Paxlovid^® should be provided with clear dosing instructions and advised that the pack provided may contain more tablets than required for their course.