4. Drug-Drug Interactions
Patient profiles will be assessed to identify those drug regimens, which may result in clinically significant drug-drug interactions. Drug-drug interactions considered clinically relevant for rifaximin are summarized in Table 2. Only those drug-drug interactions classified as clinical significance level 1 or those considered life-threatening which have not yet been classified will be reviewed.
| Interacting Drug | Interaction | Recommendation | Clinical Significance Level # |
|---|---|---|---|
| cyclosporine | adjunctive use markedly increases systemic rifaximin concentrations, as rifaximin is P-glycoprotein and OATP1B1/3 substrate, and cyclosporine is P-glycoprotein and OATP1B1/3 inhibitor | clinical significance of increased exposure unknown; observe for increased adverse effects if combined therapy necessary | 3-moderate (CP) |
| eliglustat (Cerdelga®) | adjunctive use may increase systemic rifaximin concentrations, as rifaximin is P-glycoprotein substrate, and eliglustat is P-glycoprotein inhibitor | clinical significance of increased exposure unknown; observe for increased adverse effects if combined therapy necessary | 3-moderate (CP) |
| warfarin | concurrent use may result in changes in INR levels due to an undetermined mechanism | monitor INR values and adjust warfarin doses as needed | 3-moderate (CP) |
Legend:
- #CP = Clinical Pharmacology
- INR = international normalized ratio