( 4 , 5.1 , 7 , 12.3 ) 7.1 Potential for PAXLOVID to Affect Other Drugs PAXLOVID (nirmatrelvir co-packaged with ritonavir) is a strong inhibitor of CYP3A, and an inhibitor of CYP2D6, P-gp and OATP1B1. 7.2 Potential for Other Drugs to Affect PAXLOVID Nirmatrelvir and ritonavir are CYP3A substrates; therefore, drugs that induce CYP3A may decrease nirmatrelvir and ritonavir plasma concentrations and reduce PAXLOVID therapeutic effect [see Contraindications (4) and Drug Interactions (7.3) Table 2 ] . Anticancer drugs apalutamide, enzalutamide ↓ nirmatrelvir/ritonavir Co-administration contraindicated due to potential loss of virologic response and possible resistance [see Contraindications (4) ].
Source: FDA drug label - nirmatrelvir and ritonavir