Naldemedine and Phenytoin interaction
Naldemedine and Phenytoin: the Naldemedine prescribing label flag this combination with the strongest language, such as a contraindication, a boxed warning, or an instruction to avoid it.
Do not combine without a prescriber's guidance. The label language below is the strongest FDA uses.
What the FDA labels say
From the Naldemedine (SYMPROIC) label · effective 2025-07-25
John's Wort) Clinical Impact Significant decrease in plasma naldemedine concentrations, which may reduce efficacy [see Clinical Pharmacology (12.3) ] Intervention Avoid use of SYMPROIC with strong CYP3A inducers.
Strong CYP3A inducers (e.g., rifampin) : Decreased naldemedine concentrations; avoid concomitant use ( 7 )
Table 3: Clinically Relevant Interactions Affecting Naldemedine When Co-Administered with Other Drugs Strong CYP3A Inducers (e.g., rifampin, carbamazepine, phenytoin, St.
Taking more than these two? Interactions stack. Check your whole list at once; it stays in your browser.
Open in the checkerNot medical advice. Interaction Checker quotes FDA label text and NIH fact sheets. Whether an interaction matters for you depends on doses, timing, kidney and liver function, and other conditions. Confirm with a pharmacist or prescriber.