Christchurch Medicines Information Service

Background Pfizer state in their prescribing information that both nirmatrelvir and ritonavir tablets should be swallowed whole and not chewed, broken, or crushed. [1] This is due to a lack of pharmacokinetic data to support administration in this manner. However, a Phase 1 study with a nirmatre...

This page was last updated: 12 August 2022 at 4:45pm Ritonavir increases (boosts) the concentration of nirmatrelvir by inhibiting its clearance by CYP3A enzymes. This also increases the concentration of other drugs metabolised by CYP3A. The tables below provide guidance on adjusting doses of pat...