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Alert to Health Care Professionals about a potential drug-drug interaction between Paxlovid and anticoagulants

In patients who are receiving a direct oral anticoagulant (DOAC), especially apixaban and rivaroxaban, and may be eligible to receive the antiviral drug Paxlovid for the treatment of COVID-19, health care professionals should be aware of a potential drug-drug interaction between DOACs and a component of Paxlovid (ritonavir).

There is evidence that patients who take DOACs and ritonavir at the same time will develop higher DOAC levels (increased anticoagulant effect) that may increase patients’ risk for bleeding.

In circumstances where a patient is taking a DOAC and may be eligible to receive Paxlovid, Thrombosis Canada advises that an individualized, patient-centric approach be taken as there may be several management options (e.g., temporarily stopping the DOAC or considering an alternative to Paxlovid treatment).

Listed below are links to health advisory groups that address this issue and that may assist in decision making:

Health Canada:

https://www.canada.ca/en/public-health/services/diseases/2019-novel-coronavirus-infection/guidance-documents/considerations-nirmatrelvir-ritonavir-paxlovid.html

https://covid-vaccine.canada.ca/info/paxlovid-en.html

Ontario Science Table:

https://covid19-sciencetable.ca/sciencebrief/nirmatrelvir-ritonavir-paxlovid-what-prescribers-and-pharmacists-need-to-know/

Alberta Health Services:

https://www.albertahealthservices.ca/assets/info/ppih/if-ppih-covid-19-paxlovid-faq-hcw.pdf

For a listing of other potential interactions between DOACs and other drugs, please refer to the Thrombosis Canada resource on DOAC drug-drug interactions:

https://thrombosiscanada.ca/wp-uploads/uploads/2021/09/DDI-Tool-Final-English.pdf