Concomitant therapy with ritonavir-containing regimen - no dose adjustment is needed; the dose of Paxlovid is 300 mg/100 mg twice daily for 5 days. Patients diagnosed with hepatitis C virus (HCV) infection who are receiving ritonavir-containing regimen should continue their treatment as indicated.

No dosage adjustment is required when co-administered with other products containing ritonavir or cobicistat. Patients on ritonavir- containing HCV regimens should continue their treatment as indicated. Monitor for increased Paxlovid or HCV drug adverse events with concomitant use. Coadministration may increase ombitasvir and paritaprevir concentrations. Refer to the ombitasvir/paritaprevir/ritonavir label for further information.