NutriStack
Amiodarone and St. John's Wort, a conflict.
St. John's Wort induces CYP3A4, which is a major metabolic pathway for amiodarone. This can significantly reduce amiodarone plasma levels, potentially causing loss of antiarrhythmic control and life-threatening recurrence of cardiac arrhythmias.
One pair, every claim cited. The two substances, the type, the mechanism, the recommendation, and the primary literature.
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From the interaction database
What the row says.
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At a glance
- Substances
- Amiodarone and St. John's Wort
- Pair type
- Conflict
- Evidence (highest tier)
- Moderate
- Source citations
- 1 source
- Stack Score effect
- −10 to your Stack Score (per scored conflict row).
- Scope
- Supplement × Prescription
- Last verified
- May 30, 2026
Conflict · Moderate evidence
Conflict
What is happening. St. John's Wort induces CYP3A4, which is a major metabolic pathway for amiodarone. This can significantly reduce amiodarone plasma levels, potentially causing loss of antiarrhythmic control and life-threatening recurrence of cardiac arrhythmias.
Mechanism. Amiodarone is primarily metabolized by CYP3A4 to its active metabolite desethylamiodarone. St. John's Wort's potent CYP3A4 induction via PXR activation can accelerate amiodarone metabolism, reducing both parent drug and metabolite levels below the therapeutic range.
Recommendation. Do not combine St. John's Wort with amiodarone. Loss of arrhythmia control can be life-threatening. Discuss alternative mood support options with your cardiologist.
Stack Score
How this pair moves the number.
Effect on the composite score
If both Amiodarone and St. John's Wort are in the same stack, this pair applies −10 to your Stack Score (per scored conflict row).
The full algorithm, the clamping rules, and four worked stacks are documented at /methodology/stack-score.
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