Liverpool COVID-19 Interactions

Do Not Coadminister

Nirmatrelvir/ritonavir (5 days)

Venetoclax

Quality of Evidence: Very Low

Summary:

Coadministration with nirmatrelvir/ritonavir has not been studied and is contraindicated. Use an alternative COVID-19 treatment. Venetoclax is metabolised by CYP3A4 and concentrations are expected to increase due to strong inhibition of CYP3A4 by nirmatrelvir/ritonavir. Coadministration with ritonavir (50 mg once daily for 14 days increased venetoclax Cmax and AUC by 2.4-fold and 7.9-fold. Coadministration with strong CYP3A4 inhibitors (such as nirmatrelvir/ritonavir) is contraindicated at initiation and during the dose-titration phase to minimize the risk of tumour lysis syndrome.

Description:

Serum concentrations may be increased due to CYP3A inhibition by ritonavir, resulting in increased risk of tumour lysis syndrome at the dose initiation and during the ramp-up phase. For patients who have completed the ramp-up phase and are on a steady daily dose of venetoclax, reduce the venetoclax dose by at least 75% when used with strong CYP3A inhibitors (refer to the venetoclax SmPC for dosing instructions).

Paxlovid GB Summary of Product Characteristics, Pfizer Ltd, December 2024.

Coadministration is contraindicated. Serum concentrations may be increased due to CYP3A inhibition by ritonavir, resulting in increased risk of tumour lysis syndrome at the dose initiation and during the ramp-up phase and is therefore contraindicated. For patients who have completed the ramp-up phase and are on a steady daily dose of venetoclax, reduce the venetoclax dose to 100 mg or less (or by at least 75% if already modified for other reasons) when used with strong CYP3A inhibitors.

Paxlovid EU Summary of Product Characteristics, Pfizer, February 2025.

Venetoclax concentrations may be increased. Avoid use of venetoclax. For further information, refer to individual product label for anticancer drug.

Paxlovid US Prescribing Information, Pfizer Inc, February 2025.