Liverpool COVID-19 Interactions

Do Not Coadminister

Nirmatrelvir/ritonavir (5 days)

Relugolix

Quality of Evidence: Very Low

Summary:

Coadministration has not been studied and is not recommended. Relugolix is mainly metabolized by CYP3A4 and to a lesser extent by CYP2C8 and is a substrate of P-gp. Nirmatrelvir/ritonavir is a strong inhibitor of CYP3A4 and P-gp and is expected to increase relugolix exposure. Coadministration of erythromycin (a P-gp inhibitor and moderate CYP3A4 inhibitor) increased relugolix AUC by 6.2-fold. A similar effect is expected with nirmatrelvir/ritonavir. The decision to pause relugolix treatment should be made in conjunction with the patient’s oncologist. If it is decided to pause relugolix treatment, restart relugolix 3 days after completing nirmatrelvir/ritonavir given that CYP3A4 inhibition by ritonavir takes several days to resolve. Treatment with relugolix may be interrupted for up to two weeks if a short course of treatment with a P-gp inhibitor is required. Alternatively, if coadministration is unavoidable, take relugolix at least 6 hours prior to the P-gp inhibitor and monitor patients more frequently for adverse reactions. If treatment with relugolix is interrupted for more than 7 days, resume administration of relugolix with a 360 mg loading dose on the first day, followed by 120 mg once daily.

Description:

(See Summary)