Table 3. Drug-Drug Interactions for Relugolix and Concomitant Drugs.
| Concomitant drug (route of administration) | Clinically meaningful effects on concomitant drugs or clearance pathways | Other metabolism or transporter pathways affected (in vitro data) | Dose adjustment required for concomitant drug | Relugolix dose adjustment recommendation with concomitant drug |
|---|---|---|---|---|
| Abiraterone (oral) | Inhibitor of CYP2D6 and CYP2C8 | OATP1B1 inhibition | No | No |
| Docetaxel (intravenous) | None reported | None reported | No | No |
| Apalutamide (oral) | Strong inducer of CYP3A4 and CYP2C19, and a weak inducer of CYP2C9. Inducer of P-gp, BCRP, and OATP1B1 | OCT2, OAT3, and MATE inhibition | No | Yesa |
| Darolutamide (oral) | Inhibitor of BCRP, OATP1B1, and OATP1B3 transporters. No clinically relevant interaction with dabigatran (P-gp substrate) | None reported | No | No |
| Enzalutamide (oral) | Strong CYP3A4 inducer and a moderate CYP2C9 and CYP2C19 inducer | P-gp and BCRP inhibition | No | No |
Note. Janssen Biotech, Inc. (2021); Sanofi-aventis (2020); Bayer (2023); Astellas Pharma Inc. (2023); Janssen Pharmaceutical Companies (2023); Myovant Sciences (2023).
aFor combined P-gp and strong CYP3A inducers like apalutamide, the relugolix prescribing information recommends to avoid coadministration. If coadministration with apalutamide is unavoidable, increase the relugolix dose to 240 mg once daily.