Answer
St John's wort should not be taken with phenytoin because it induces drug-metabolising enzymes and can lower phenytoin blood levels, with this effect potentially persisting for at least two weeks after St John's wort is stopped.
Sources for this answer
- Epanutin 30mg/5ml oral SuspensionViatris (formerly Mylan or Upjohn) · emc · SmPC §4.5 Interaction with other medicinal products · Version 28Document updated
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