NutriStack
Diltiazem and St. John's Wort, a conflict.
St. John's Wort induces CYP3A4, reducing diltiazem plasma levels significantly. This can lead to uncontrolled hypertension or angina.
One pair, every claim cited. The two substances, the type, the mechanism, the recommendation, and the primary literature.
Same shape as the other 1,729 pairs in the public database.
From the interaction database
What the row says.
Every entry follows the same shape: what is happening, the mechanism, the recommendation, and the primary literature.
At a glance
- Substances
- Diltiazem and St. John's Wort
- Pair type
- Conflict
- Evidence (highest tier)
- Strong
- 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 · Strong evidence
Conflict
What is happening. St. John's Wort induces CYP3A4, reducing diltiazem plasma levels significantly. This can lead to uncontrolled hypertension or angina.
Mechanism. Diltiazem is a CYP3A4 substrate. Hyperforin-mediated CYP3A4 induction increases diltiazem metabolism, reducing its bioavailability and therapeutic effect.
Recommendation. Avoid combining St. John's Wort with diltiazem.
Stack Score
How this pair moves the number.
Effect on the composite score
If both Diltiazem 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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