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St John's wort and DOAC — GPhC CRA MCQ

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ModerateDrug InteractionsSt John's wort and DOACGPhC CRA

A patient taking rivaroxaban asks whether St John's wort would be suitable for low mood while waiting for a GP appointment. What is the most important interaction to flag?

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Correct answer: D — Reduced anticoagulant exposure and possible loss of effect

St John's wort induces drug-metabolising enzymes and transporters and can reduce exposure to several medicines. With rivaroxaban this may reduce anticoagulant effect and increase thrombotic risk. It also interacts with many antidepressants and other medicines. The patient should be advised not to start it and to seek appropriate mental health support.

Reference: BNF